ICSE

Selina Publishers Concise Mathematics Class 7 ICSE Solutions Chapter 8 Percent and Percentage

Selina Publishers Concise Mathematics Class 7 ICSE Solutions Chapter 8 Percent and Percentage

Percent and Percentage Exercise 8A – Selina Concise Mathematics Class 7 ICSE Solutions

Question 1.
Express each of the following as percent :

Solution :

Question 2.
Express the following percentages as fractions and as decimal numbers :

Solution :

Question 3.
What percent is :
(i) 16 hours of 2 days ?
(ii) 40 paisa of Rs. 2 ?
(iii) 25 cm of 4 metres
(iv) 600 gm of 5 kg ?
Solution :

Question 4.
Find the value of:

Solution :

Question 5.
In a class of 60 children, 30% are girls. How many boys are there ?
Solution :

Question 6.
In an election, two candidates A and B contested. A got 60% of the votes. The total votes polled were 8000. How many votes did each get ?
Solution :

Question 7.
A person saves 12% of his salary every month. If his salary is ₹2,500, find his expenditure.
Solution :

Question 8.
Seeta got 75% marks out of a total of 800. How many marks did she lose ?
Solution :

Question 9.
A shop worth ₹25,000 was insured for 95% of its value. How much would the owner get in case of any mishappening ?
Solution :

Question 10.
A class has 30 boys and 25 girls. What is the percentage of boys in the class ?
Solution :

Question 11.
Express :
(i) 3 \(\frac { 2 }{ 5 }\) as a percent
(ii) 0.0075 as percent
(iii) 3 : 20 as percent
(iv) 60 cm as percent of 1 m 25 cm
(v) 9 hours as a percent of 4 days.
Solution :

Question 12.
(i) Find 2% of 2 hours 30 min.
(ii) What percent of 12 kg is 725 gm?
Solution :

Percent and Percentage Exercise 8B – Selina Concise Mathematics Class 7 ICSE Solutions

Question 1.
Deepak bought a basket of mangoes containing 250 mangoes 12% of these were found to be rotten. Of the remaining, 10% got crushed. How many mangoes were in good condition ?
Solution :

Question 2.
In a Maths Quiz of 60 questions, Chandra got 90% correct answers and Ram got 80% correct answers. How many correct answers did each give ?
What percent is Ram’s correct answers to Chandra’s correct answers ?
Solution :

Question 3.
In an examination, the maximum marks are 900. A student gets 33% of the maximum marks and fails by 45 marks. What is the passing mark ? Also, find the pass percentage.
Solution :

Question 4.
In a train, 15% people travel in first class, 35% travel in second class. The balance travel in the A.C. class ? Calculate the percentage of A.C. class travellers ?
Solution :

Question 5.
A boy eats 25% of the cake and gives away 35% of it to his friends. What percent of the cake is still left with him ?
Solution :

Question 6.
What is the percentage of vowels in the English alphabet ?
Solution :

Question 7.

Solution :

Question 8.
The money spent on the repairs of a house was 1% of its value. If the repair, costs Rs. 5,000, find the cost of the house.
Solution :

Question 9.
In a school out of300 students, 70% are girls and 30% are boys. If 30 girls leave and no new boy is admitted, what is the new percentage of girls in the school ?
Solution :

Question 10.
Kumar bought a transistor for Rs. 960. He paid 12 \(\frac { 1 }{ 2 }\) % cash money. The rest he agreed to pay in 12 equal monthly instalments. How much will he pay each month ?
Solution :

Question 11.
An ore contains 20% zinc. How many kg of ore will be required to get 45 kg of zinc ?
Solution :

Percent and Percentage Exercise 8C – Selina Concise Mathematics Class 7 ICSE Solutions

Question 1.
The salary of a man is increased from Rs. 600 per month to Rs. 850 per month. Express the increase in salary as percent.
Solution :

Question 2.
Increase :
(i) 60 by 5%
(ii) 20 by 15%
(iii) 48 by 121 %
(iv) 80 by 140%
(v) 1000 by 3.5%
Solution :

Question 3.
Decrease :
(i)80 by 20%
(ii) 300 by 10%
(iii) 50 by 12.5%
Solution :

Question 4.
What number :
(i) When increased by 10% becomes 88 ?
(ii) When increased by 15% becomes 230 ?
(iii) When decreased by 15% becomes 170 ?
(iv) When decreased by 40% becomes 480 ?
(v) When increased by 100% becomes 100 ?
(vi) When decreased by 50% becomes 50 ?
Solution :

Question 5.
The price of a car is lowered by 20% to Rs. 40,000. What was the original price ? Also, find the reduction in price.
Solution :

Question 6.
If the price of an article is increased by 25%, The increase is Rs. 10. Find the new price.
Solution :

Question 7.
If the price of an article is reduced by 10%, the reduction is Rs. 40. What is the old price ?
Solution :

Question 8.
The price of a chair is reduced by 25%. What is the ratio of:
(i) Change in price to the old price.
(ii) Old price to the new price.
Solution :

Question 9.
If x is 20% less than y, find :

Solution :

Question 10.
If x is 30% more than y; find :

Solution :

Question 11.
The weight of a machine is 40 kg. By mistake it was weighed as 40.8 kg. Find the error percent.
Solution :

Question 12.
From a cask, containing 450 litres of petrol, 8% of the petrol was lost by leakage and evaporation. How many litres of petrol was left in the cask ?
Solution :

Question 13.
An alloy consists of 13 parts of copper, 7 parts of zinc and 5 parts of nickel. What is the percentage of each metal in the alloy?
Solution :

Question 14.
In an examination, first division marks are 60%. A student secures 538 marks and misses the first division by 2 marks. Find the total marks of the examination.
Solution :

Question 15.
Out of 1200 pupils in a school, 900 are boys and the rest are girls. If 20% of the boys and 30% of the girls wear spectacles, find :
(i) how many pupils in all, wear spectacles ?
(ii) what percent of the total number of pupils wear spectacles ?
Solution :

Question 16.
Out of 25 identical bulbs, 17 are red, 3 are black and the remaining are yellow. Find the difference between the numbers of red and yellow bulbs and express this difference as percent.
Solution :

Question 17.
A number first increases by 20% and then decreases by 20%. Find the percentage increase or decrease on the whole.
Solution :

Question 18.
A number is first decreased by 40% and then again decreased by 60%. Find the percentage increase or decrease on the whole.
Solution :

Question 19.
If 150% of a number is 750, find 60% of this number.
Solution :

Selina Concise Mathematics Class 7 ICSE Solutions

Selina Concise Mathematics Class 6 ICSE Solutions Chapter 24 Angles (With their Types)

Selina Publishers Concise Mathematics Class 6 ICSE Solutions Chapter 24 Angles (With their Types)

Angles Exercise 24A – Selina Concise Mathematics Class 6 ICSE Solutions

Question 1.
For each angle given below, write the name of the vertex, the names of the arms and the name of the angle.

Solution:

Question 2.
Name the points :
(i) in the interior of the angle PQR,
(ii) in the exterior of the angle PQR.

Solution:

Question 3.
In the given figure, figure out the number of angles formed within the arms OA and OE.

Solution:

Question 4.
Add :
(i) 29° 16′ 23″ and 8° 27′ 12″
(ii) 9° 45’56” and 73° 8′ 15″
(m) 56° 38′ and 27° 42’30”
(iv) 47° and 61° 17’4″
Solution:

Question 5.
In the figure, given below name :
(i) three pairs of adjacent angles.
(ii) two acute angles,
(iii) two obtuse angles
(iv) two reflex angles.

Solution:

Question 6.
In the given figure ; PQR is a straight line. If :
(i) ∠SQR = 75° ; find ∠PQS.
(ii) ∠PQS = 110°; find ∠RQS

Solution:

Question 7.
In the given figure ; AOC-is a straight line. If angle AOB = 50°, angle AOE = 90° and angle COD = 25° ; find the measure of :
(i) angle BOC
(ii) angle EOD
(iii) obtuse angle BOD
(iv) reflex angle BOD
(v) reflex angle COE.

Solution:

Question 8.
In the given figure if :
(i) a = 130° ; find b.
(ii) b = 200 ; find a.
(iii) a = 5/3 right angle, find b

Solution:

Question 9.
In the given diagram, ABC is a straight line.
(i) If x = 53°, find y.
(ii) If y =1\(\frac { 1 }{ 2 }\) right angles ; find x.

Solution:

Question 10.
In the given figure, AOB is a straight line. Find the value ofx and also answer each of the following :
(i) ∠AOP = ……..
(ii) ∠BOP = ……..
(iii) which angle is obtuse ?
(iv) which angle is acute ?

Solution:

Question 11.
In the given figure, PQR is a straight line. Find x. Then complete the following:
(i) ∠AQB = ……..
(ii) ∠BQP = ……..
(iii) ∠AQR = …….

Solution:

Question 12.
In the given figure, lines AB and CD intersect at point O.
(i) Find the value of ∠a.
(ii) Name all the pairs of vertically opposite angles.
(iii) Name all the pairs of adjacent angles.
(iv) Name all the reflex angles formed and write the measure of each.

Solution:

Question 13.
In the given figure :
(i) If ∠AOB = 45°, ∠BOC = 30° and ∠AOD= 110°;
find : angles COD and BOD.
(ii) If ∠BOC = ∠DOC = 34° and ∠AOD = 120° ;
find : angle AOB and angle AOC.
(iii) If ∠AOB = ∠BOC = ∠COD = 38°
find : reflex angle AOC and reflex angle AOD.

Solution:

Angles Exercise 24B – Selina Concise Mathematics Class 6 ICSE Solutions

Question 1.
Write the complement angle of :
(i) 45°
(ii) x°
(iii) (x – 10)°
(iv) 20° + y°
Solution:

Question 2.
Write the supplement angle of :
(i) 49°
(ii) 111°
(iii) (x – 30)°
(iv) 20° + y°
Solution:

Question 3.
Write the complement angle of :


Solution:

Question 4.

Solution:

Question 5.
Find the angle :
(i) that is equal to its complement ?
(ii) that is equal to its supplement ?
Solution:

Question 6.
Two complementary angles are in the ratio 7 : 8. Find the angles.
Solution:

Question 7.
Two supplementary angles are in the ratio 7 : 11. Find the angles.
Solution:

Question 8.
The measures of two complementary angles are (2x – 7)° and (x + 4)°. Find x.
Solution:

Question 9.
The measures of two supplementary angles are (3x + 15)° and (2x + 5)°. Find x.
Solution:

Question 10.
For an angle x°, find :
(i) the complementary angle
(ii) the supplementary angle
(iii) the value of x° if its supplementary angle is three times its complementary angle.
Solution:

Angles Revision Exercise – Selina Concise Mathematics Class 6 ICSE Solutions

Question 1.
Explain what do you understand by :
(i) Adjacent angles ?
(ii) Complementary angles ?
(iii) Supplementary angles ?
Solution:

Question 2.
Find the value of ‘x’ for each of the following figures :


Solution:

Question 3.
Find the number of degrees in an angle that is (i) \(\frac { 3 }{ 5 }\) of a right angle (ii) 0.2 times of a straight line angle.
Solution:

Question 4.
In the given figure; AB, CD and EF are straight lines. Name the pair of angles forming :
(i) straight line angles.
(ii) vertically opposite angles.

Solution:

Question 5.
Find the complement of :

Solution:

Question 6.
Find the supplement of :

Solution:

Question 7.
Two complementary angles are in the ratio 8 : 7. Find the angles.
Solution:

Question 8.
Two supplementary angles are in the ratio 7 : 5. Find the angles.
Solution:

Question 9.
Two supplementary angles are (5x – 82°) and (4x + 73°). Find the value of x.
Solution:

Question 10.
Find the angle formed by the arms of a clock at:
(i) 3 O’clock
(ii) 6 O’clock
(iii) 9 O’clock
(iv) 12 O’clock
Solution:

Question 11.
For an angle y°, find :
(i) its supplementary angle.
(ii) its complementary angle.
(iii) the value of y° if its supplement is four times its complement.
Solution:

Question 12.
Use the adjoining figure to find :
(i) ∠BOD
(ii) ∠AOC
Solution:

Question 13.
Two adjacent angles forming a linear pair are in the ratio 7:5, find the angles.
Solution:

Question 14.
Find the angle that is three times its complementary angle.
Solution:

Question 15.
An angle is one-thirds of a straight line angle ; find :
(i) the angle
(ii) the complement and the supplement of the angle obtained above.
Solution:

Selina Concise Mathematics Class 6 ICSE Solutions

Selina Concise Mathematics Class 6 ICSE Solutions Chapter 23 Fundamental Concepts

Selina Publishers Concise Mathematics Class 6 ICSE Solutions Chapter 23 Fundamental Concepts

Fundamental Concepts Exercise 23A – Selina Concise Mathematics Class 6 ICSE Solutions

Question 1.
State, true or false, if false, correct the statement.
(i) A dot has width but no length.
(ii) A ray has an infinite length only on one side of it.
(iii) A line segment PQ is written as \(\overleftrightarrow { PQ }\) .
(iv) \(\overleftrightarrow { PQ }\)  represents a straight line.
(v) Three points are said to be collinear, if they lie in the same plane.
(vi) Three or more points all lying in the same line, are called collinear points.
Solution:

Question 2.
Write how many lines can be drawn through :
(i) a given point?
(ii) two given fixed points?
(iii) three collinear points?
(iv) three non-collinear points?
Solution:

Question 3.
The shaded region of the given figure shows a plane :
(a) Name :
(i) three collinear points.
(ii) three non-collinear points.
(iii) a pair of intersecting lines.
(b) State whether true or false :
(i) Line DE is contained in the given plane P.
(ii) Lines AB and DE intersect at point C.
(iii) Points D, B and C are collinear.
(iv) Points D, B and E are collinear.
Solution:

Question 4.
Correct the statement, if it is wrong:
(i) A A ray can be extended infinitely on either side.
(ii) A ray has a definite length.
(iii) A line segment has a definite length.
(iv) A line has two end-points.
(v) A ray has only one end point.
Solution:

Question 5.
State true-er false, if false give the correct statement :
(i) A line has a countable number of points in it.
(ii) Only one line can pass through a given point.
(iii) The intersection of two planes is a straight line
Solution:

Question 6.
State, whether the following pairs of lines or rays appear to be parallel or intersecting.


Solution:

Question 7.
Give two examples, from your surroundings, for each of the following:
(i) points
(ii) line segments
(iii) plane surfaces
(iv) curved surfaces.
Solution:

Question 8.
Under what condition will two straight
lines, in the same plane, have :
(i) no point in common.
(ii) only one point in common.
(iii) an infinite number of points in common.
(iv) If possible draw diagrams in support of your answer.
Solution:

Question 9.
Mark two points A and B on a page of your exercise book. Mark a third point P, such that :
(i) P lies between A and B; and the three points A, P and B are collinear.
(ii) P does not lie between A and B yet the three points are collinear.
(iii) the three points do not lie in a line.
Solution:

Question 10.
Mark two points P and Q on a piece of paper. How many lines can you draw:
(i) passing through both the points P and Q?
(ii) passing through the point P ?
(iii) passing through the point Q ?
Solution:

Question 11.
The adjoining diagram shows a line AB. Draw diagram to represent:
(i) ray AB i.e. \(\overrightarrow { AB } \)

(ii) \(\overrightarrow { BA } \)
(iii) line segment AB.
Solution:

Question 12.
The adjoining diagram shows a ray AB. Draw diagrams to show :
(i) ray BA i.e. \(\overrightarrow { BA } \)
(ii) lineAB
(iii) line segment BA.

Solution:

Question 13.
The adjoining diagram shows a line segment AB. Draw diagrams to represent :
(i) ray AB i.e. \(\overrightarrow { AB } \)
(ii) line AB i.e. \(\overleftrightarrow { AB }\)
(iii) ray BA.

Solution:

Question 14.
Use a ruler and And whether the following points are collinear or not:
(i) D, A and C
(ii) A, B and C
(iii) A, B and E
(iv) B, C and E

Solution:

Question 15.
From the adjoining figure, write:
(i) all pairs f parallel lines
(ii) all the lines which intersect EF.
(iii) lines whose point of intersection is G.

Solution:

Fundamental Concepts Exercise 23B – Selina Concise Mathematics Class 6 ICSE Solutions

Question 1.
State, which of the following is a plane closed figure :

Solution:

Question 2.
Fill in the blanks :
(i) ….. is a three sided plane closed figure.
(ii) A square is a plane closed figure which is not bounded by …..
(iii) A rectangle is a …. sided plane ……
(iv) A rectangle has opposite sides ….. and adjacent sides ….. to each other.
(v) The sides of a square are ……. to each other and each angle is
(vi) For a line segment, a line making angle of ……… with it, is called perpendicular to it.
(vii) For a line segment, a line ……. it and making angle of ……. with it, is called ……. bisector of the line segment.
(viii) How many perpendiculars can be drawn to a line segment of length 6 cm ?
(ix) How many perpendicular bisectors can be drawn to a line segment of length 6 cm ?
(x) A perpendicular to a line segment will be its perpendicular bisector if it passes through the ……. of the given line segment.
Solution:

Question 3.
State, which of the lines/line- segments are perpendicular to the line PQ :

Solution:

Question 4.
Which of the following figures show two mutually perpendicular lines :

Solution:

Question 5.
For each figure given below name the line segment that is perpendicular bisector of the other :

Solution:

Question 6.
Name three objects from your surroundings that contain perpendicular edges.
Solution:

Question 7.
Using the given figure, answer the following :
(i) Name the pairs of parallel lines.
(ii) Name the pairs of mutually perpendicular lines.
(iii) Is the line p parallel to the line l ?
(iv) Is the line q perpendicular to the line m ?

Solution:

Question 8.
Place a scale (ruler) on a sheet of paper and hold it firmly with one hand. Now draw two line segments AB and CD along the longer edges of the scale. State whether segment AB is parallel to or perpendicular to segment CD.
Solution:

Question 9.
Check your text book :
(i) How many pairs of its edges are parallel to each other ?
(ii) How many pairs of its edges are perpendicular to each other ?
Solution:

Question 10.
Give two examples from your surroundings for each of the following :
(i) intersecting lines
(ii) parallel lines
(iii) perpendicular lines.
Solution:

Question 11.
State true or false; if false, give the correct statement :
(i) The maximum number of lines through three collinear points is three.
(ii) The maximum number of lines through three non-collinear points is three.
(iii) Two parallel lines always lie in the same plane.
(iv) Concurrent lines always meet at the same point.
(v) A surface can be plane or curved.
(vi) There are an infinite number of points in a line segment of length 10 cm.
(vii) There are an infinite number of points in a line.
(viii) A plane has an infinite number of lines.
(ix) A plane has an infinite number of points.
Solution:

Fundamental Concepts Revision Exercise – Selina Concise Mathematics Class 6 ICSE Solutions

Question 1.
Mark a point O on a piece of paper. Using a sharp pencil and a ruler, draw a line through the point O. Then draw one more line through the point O. How many lines can you draw through O?
Write a statement regarding your observations.
Solution:

Question 2.
Mark two points A and B on a plain sheet “ of paper. Using a sharp pencil and a ruler, draw a line through points A and B. Try to draw one more line through A and B. What do you observe ?
Write a statement regarding your observations.
Solution:

Question 3.
Draw two straight lines on a sheet of paper so that the lines drawn :
(i) intersect each other.
(ii) do not intersect.
(iii) appear to intersect when extended.
Solution:

Question 4.
Draw a figure to show that :
(i) points A, B and C arc collinear.
(ii) lines AB, CD and EF are concurrent.
Solution:

Question 5.
In your note-book, draw two rays with the same initial point O and going in opposite directions. Write the special name for the final figure obtained.
Solution:

Question 6.
In each figure, given below, write the number of line segments used :

Solution:

Question 7.
In a circle, point P is its centre and PA = PB = radius of the circle. Where do points A and B lie ?
Solution:

Question 8.
Draw a four-sided closed figure, in which:
(i) all the sides are equal and each angle is 90°.
(ii) opposite sides are equal and each angle is 90°.
Write the special name of each figure drawn.
Solution:

Selina Concise Mathematics Class 6 ICSE Solutions

Selina Publishers Concise Mathematics Class 7 ICSE Solutions Chapter 7 Unitary Method (Including Time and Work)

Selina Publishers Concise Mathematics Class 7 ICSE Solutions Chapter 7 Unitary Method (Including Time and Work)

Unitary Method Exercise 7A – Selina Concise Mathematics Class 7 ICSE Solutions

Question 1.
Weight of 8 identical articles is 4.8 kg. What is the weight of 11 such articles ?
Answer:

Question 2.
6 books weigh 1 .260 kg. How many books will weigh 3.150 kg ?
Answer:

Question 3.
8 men complete a work in 6 hours. In how many hours will 12 men complete the same work ?
Answer:

Question 4.
If a 25 cm long candle burns for 45 minutes, how long will another candle of the same material and same thickness but 5 cm longer than the previous one, burn ?
Answer:

Question 5.
A typist takes 80 minutes to type 24 pages. How long will he take to type 87 pages ?
Answer:

Question 6.
Rs. 750 support a family for 15 days. For how many days will Rs. 2,500 support the same family ?
Answer:

Question 7.
400 men have provisions for 23 weeks. They are joined by 60 men. How long will the provisions last ?
Answer:

Question 8.
200 men have provisions for 30 days. If 50 men left, the same provisions would last for the remaining men, in how many days?
Answer:

Question 9.
8 men can finish a certain amount of provisions in 40 days. If 2 more men join with them, find for how many days the same amount of provisions be sufficient ?
Answer:

Question 10.
If interest on Rs. 200 be Rs. 25 in a certain time, what will be the interest on Rs 750 for the same time ?
Answer:

Question 11.
If 3 dozen eggs cost Rs. 90, find the cost of 3 scores of eggs. (1 score = 20)
Answer:

Question 12.
If the fare for 48 km is Rs. 288, what will be the fare for 36 km ?
Answer:

Question 13.
What will be the cost of 3.20 kg of an item, if 3 kg of it costs Rs. 360 ?
Answer:

Question 14.
If 9 lines of a print, in a column of a book contains 36 words. How many words will a column of 51 lines cqntain ?
Answer:

Question 15.
125 pupil have food sufficient for 18 days. If 25 more pupil join them, how long will the food last now ? What assumption have you made to come to your answer ?
Answer:

Question 16.
A carpenter prepares a new chair in 3 days, working 8 hours a day. Atleast how many hours per day must he work in order to make the same chair in 4 days ?
Answer:

Question 17.
A man earns ₹5,800 in 10 days. How much will he earn in the month of February of a leap year?
Answer:

Question 18.
A machine is used for making rubber balls and makes 500 balls in 30 minutes. How many balls will it make in 3\(\frac { 1 }{ 2 }\) hours?
Answer:

Question 19.
In a school’s hostel mess, 20 children consume a certain quantity of ration in 6 days. However, 5 children did not return to the hostel after holidays. How long will the same amount of ration last now?
Answer:

Unitary Method Exercise 7B – Selina Concise Mathematics Class 7 ICSE Solutions

Question 1.

Answer:

Question 2.
3\(\frac { 1 }{ 2 }\)m of cloth costs Rs. 168 ; find the cost of 4\(\frac { 1 }{ 3 }\)m of the same cloth.
Answer:

Question 3.
A wrist watch loses 10 sec in every 8 hours; in how much time will it lose 15 sec. ?
Answer:

Question 4.
In 2 days and 20 hours, a watch gains 20 sec ; find how much time will the watch take to gain 35 sec. ?
Answer:

Question 5.
50 men mow 32 hectares of land in 3 days. How many days will 15 men take to mow it?
Answer:

Question 6.
The wages of 10 workers for a six days week are Rs, 1,200. What are the one day wages: (i) of one worker ? (ii) of 4 workers?
Answer:

Question 7.
If 32 apples weigh 2 kg 800 g. How many apples will there be in a box, containing 35 kg of apples ?
Answer:

Question 8.
A truck uses 20 litres of diesel for 240 km. How many litres will be needed for 1200 km?
Answer:

Question 9.
A garrison of 1200 men has provisions for 15 days. How long will the provisions last if the garrison be increased by 600 men ?
Answer:

Question 10.
A camp has provisions for 60 pupil for 18 days. In how many days, the same provisions will finish off if the strength of the camp is increased to 72 pupil ?
Answer:

EXERCISE 7 (C)

Question 1.
A can do a piece of work in 6 days and B can do it in 8 days. How long will they take to complete it together ?
Answer:

Question 2.
A and B working together can do a piece of work in 10 days B alone can do the same work in 15 days. How long will A alone take to do the same work ?
Answer:

Question 3.
A can do a piece of work in 4 days and B can do the same work in 5 days. Find, how much work can be done by them working together in : (i) one day (ii) 2 days.
What part of work will be left, after they have worked together for 2 days ?
Answer:

Question 4.
A and B take 6 hours and 9 hours respectively to complete a work. A works for 1 hour and then B works for two hours.
(i) How much work is done in these 3 hours ?
(ii) How much work is still left ?
Answer:

Question 5.
A, B and C can do a piece of work in 12, 15 and 20 days respectively. How long will they take to do it working together ?
Answer:

Question 6.
Two taps can fill a cistern in 10 hours and 8 hours respectively. A third tap can empty it in 15 hours. How long will it take to fill the empty cistern, if all of them are opened together ?
Answer:

Question 7.
Mohit can complete a work in 50 days, whereas Anuj can complete the same work in 40 days.
Find:
(i) work done by Mohit in 20 days.
(ii) work left after Mohit has worked on it for 20 days.
(iii) time taken by Anuj to complete the remaining work.
Answer:

Question 8.
Joseph and Peter can complete a work in 20 hours and 25 hours respectively.
Find :
(i) work done by both together in 4 hrs.
(ii) work left after both worked together for 4 hrs.
(iii) time taken by Peter to complete the remaining work.
Answer:

Question 9.
A is able to complete \(\frac { 1 }{ 3 }\) of a certain work in 10 hrs and B is able to complete\(\frac { 2 }{ 5 }\) of the same work in 12 hrs.
Find:
(i) how much work can A do in 1 hour ?
(ii) how much work can B do in 1 hour ?
(iii) in how much time will the work be completed, if both work together.
Answer:

Question 10.
Shaheed can prepare one wooden chair in 3 days and Shaif can prepare the same chair in 4 days. If they work together, in how many days will they prepare :
(i) one chair ?
(ii)14 chairs of the same kind?
Answer:

Question 11.
A, B and C together finish a work in 4 days. If A alone can finish the same work in 8 days and B in 12 days, find how long will C take to finish the work.
Answer:

Selina Concise Mathematics Class 7 ICSE Solutions

Selina Concise Mathematics Class 6 ICSE Solutions Chapter 22 Simple (Linear) Equations (Including Word Problems)

Selina Publishers Concise Mathematics Class 6 ICSE Solutions Chapter 22 Simple (Linear) Equations (Including Word Problems)

Simple (Linear) Equations Exercise 22A – Selina Concise Mathematics Class 6 ICSE Solutions

Question 1.
Solve:


Solution:

Question 2.
Solve:

Solution:

Question 3.
Solve:

Solution:

Question 4.
Solve:

Solution:

Question 5.
Solve:

Solution:

Simple (Linear) Equations Exercise 22B – Selina Concise Mathematics Class 6 ICSE Solutions

Question 1.
Solve:


Solution:

Question 2.
Solve:

Solution:

Question 3.
Solve:

Solution:

Simple (Linear) Equations Exercise 22C – Selina Concise Mathematics Class 6 ICSE Solutions

Question 1.
5 – x = 3
Solution:

Question 2.
2 – y = 8
Solution:

Question 3.
8.4 – x = -2
Solution:

Question 4.

Solution:

Question 5.

Solution:

Question 6.

Solution:

Question 7.
1.6z = 8
Solution:

Question 8.
3a = – 2.1
Solution:

Question 9.

Solution:

Question 10.

Solution:

Question 11.
– 5x = 10
Solution:

Question 12.
2.4z = -4.8
Solution:

Question 13.
2y – 5 = -11
Solution:

Question 14.
2x + 4.6 = 8
Solution:

Question 15.
5y – 3.5 = 10
Solution:

Question 16.
3x + 2 = -2.2
Solution:

Question 17.

Solution:

Question 18.

Solution:

Question 19.

Solution:

Question 20.
-3y – 2 = 10
Solution:

Question 21.
4z – 5 = 3 – z
Solution:

Question 22.
7x – 3x + 2 =22
Solution:

Question 23.
6y + 3 = 2y + 11
Solution:

Question 24.
3 (x + 5) = 18
Solution:

Question 25.
5 (x – 2) – 2 (x + 2) = 3
Solution:

Question 26.
(5x – 3) 4 = 3
Solution:

Question 27.
3(2x + 1) – 2(x – 5) -5 (5 – 2x) = 16
Solution:

Simple (Linear) Equations Exercise 22D – Selina Concise Mathematics Class 6 ICSE Solutions

Question 1.
A number increased by 17 becomes 54. Find the number.
Solution:

Question 2.
A number decreased by 8 equals 26, find the number.
Solution:

Question 3.
One-fourth of a number added to two- seventh of it gives 135; find the number.
Solution:

Question 4.
Two-fifths of a number subtracted from three-fourths of it gives 56, find the number.
Solution:

Question 5.
A number is increased by 12 and the new number obtained is multiplied by 5. If the resulting number is 95, find the original number.
Solution:

Question 6.
A number is increased by 26 and the new number obtained is divided by 3. If the resulting number is 18; find the original number.
Solution:

Question 7.
The age of a man is 27 years more than the age of his son. If the sum of their ages is 47 years, find the age of the son and his father.
Solution:

Question 8.
The difference between the ages of Gopal and his father is 26 years. If the sum of their ages is 56 years, find the ages of Gopal and his father.
Solution:

Question 9.
When two consecutive natural numbers are added, the sum is 31; find the numbers.
Solution:

Question 10.
When three consecutive natural numbers are added, the sum is 66, find the numbers.
Solution:

Question 11.
A natural number decreased by 7 is 12. Find the number.
Solution:

Question 12.
One fourth of a number added to one- sixth of itself is 15. Find the number.
Solution:

Question 13.
A whole number is increased by 7 and the new number so obtained is multiplied by 5; the result is 45. Find the number.
Solution:

Question 14.
The age of a man and the age of his daughter differ by 23 years and the sum of their ages is 41 years. Find the age of the man.
Solution:

Question 15.
The difference between the ages of a woman and her son is 19 years and the sum of their ages is 37 years; find the age of the son.
Solution:

Question 16.
Two natrual numbers differ by 6 and sum of them is 36. Find the larger number.
Solution:

Question 17.
The difference between two numbers is 15. Taking the smaller number as x; find:
(i) the expression for larger number.
(ii) the larger number, if the sum of these numbers is 71.
Solution:

Question 18.
The difference between two numbers is 23. Taking the larger number as x, find:
(i) the expression for smaller number.
(ii) the smaller number, if the sum of these two numbers is 91.
Solution:

Question 19.
Find three consecutive integers such that their sum is 78.
Solution:

Question 20.
The sum of three consecutive numbers is 54. Taking the middle number as x, find:
(i) expression for the smallest number and the largest number.
(ii) the three numbers.
Solution:

Simple (Linear) Equations Revision Exercise – Selina Concise Mathematics Class 6 ICSE Solutions

Question 1.
Solve each of the following equations :
Question i.
2x + 3 = 7
Solution:

Question ii.
2x – 3 = 7
Solution:

Question iii.
2x ÷ 3 = 7
Solution:

Question iv.
3x – 8 = 13
Solution:

Question v.
3y + 8 = 13
Solution:

Question vi.
3y ÷ 8 = 13
Solution:

Question vii.

Solution:

Question viii.

Solution:

Question ix.

Solution:

Question x.
5x – 2.4 = 4.9
Solution:

Question xi.
5y + 4.9 = 2.4
Solution:

Question xii.
48 z + 3.6 = 1.2
Solution:

Question xiii.

Solution:

Question xiv.

Solution:

Question xv.

Solution:

Question xvi.
-3x + 4 = 10
Solution:

Question xvii.
5 = x – 3
Solution:

Question xviii.
8y = 3- 3y
Solution:

Question xix.
4x = 4.9 = 6.5
Solution:

Question xx.
3z + 2 = -4
Solution:

Question xxi.
7y – 18 = 17
Solution:

Question xxii.

Solution:

Question xxiii.

Solution:

Question xxiv.

Solution:

Question xxv.
7x – 2 = 4x + 7
Solution:

Question xxvi.
3y -(y + 2) = 4
Solution:
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Question xxvii.
3z – 18 = z – (12 – 4z)
Solution:

Question xxiii.

Solution:

Question xxix.

Solution:

Question xxx.

Solution:

Question xxxi.
5x – 2x + 15 = 27
Solution:

Question xxxii.
5y – 15 = 27 -2y
Solution:

Question xxxiii.
7z + 15 = 3z – 13
Solution:

Question xxxiv.
2 (x -3) – 3 (x-4) =12
Solution:

Question xxxv.
(7y + 8) + 7 = 8
Solution:

Question xxxvi.
2(z – 5) +3 (z + 2) -(3 – 5z) = 10
Solution:

Question 2.
A natural number decreased by 7 is 12. Find the number.
Solution:

Question 3.
One-fourth of a number added to one-sixth of It is 15. Find the number.
Solution:

Question 4.
A whole number is increased by 7 and the number so obtained is multiplied by 5; the result is 45. Find the whole number.
Solution:

Question 5.
The age of a man and the age of his daughter differ by 23 years and the sum of their ages is 41 years. Find the age of the man.
Solution:

Question 6.
The difference between the ages of a woman and her son is 19 years and the sum of their ages is 37 years; find the age of the son.
Solution:

Question 7.
Two natural numbers differ by 6 and their sum is 36. Find the larger number.
Solution:

Question 8.
The difference between two numbers is 15. Taking the smaller number as x; find :
(i) the expression for the larger number.
(ii) the larger number, if the sum of these numbers is 71.
Solution:

Question 9.
The difference between two numbers is 23. Taking the larger number as x, find :
(i) the expression for smaller number.
(ii) the smaller number, if the sum of these two numbers is 91.
Solution:

Question 10.
Find the three consecutive integers whose sum is 78.
Solution:

Question 11.
The sum of three consecutive numbers is 54. Taking the middle number as x, find :
(i) the expressions for the smallest number and the largest number.
(ii) the three numbers.
Solution:

Selina Concise Mathematics Class 6 ICSE Solutions