## RS Aggarwal Class 8 Solutions Chapter 12 Direct and Inverse Proportions Ex 12B

These Solutions are part of RS Aggarwal Solutions Class 8. Here we have given RS Aggarwal Solutions Class 8 Chapter 12 Direct and Inverse Proportions Ex 12B.

**Other Exercises**

- RS Aggarwal Solutions Class 8 Chapter 12 Direct and Inverse Proportions Ex 12A
- RS Aggarwal Solutions Class 8 Chapter 12 Direct and Inverse Proportions Ex 12B
- RS Aggarwal Solutions Class 8 Chapter 12 Direct and Inverse Proportions Ex 12C

**Question 1.**

**Solution:**

∵ x and y are inversely proportional

Then xy are equal

(i) xy = 6 x 9 = 54

= 10 x 15 = 150

= 14 x 21 = 294

= 16 x 24 = 384

∵ xy in each case is not equal

So, x and y are not inversely proportional

(ii) xy = 5 x 18 = 90

= 9 x 10 = 90

= 15 x 6 = 90

= 3 x 30 = 90

= 45 x 2 = 90

∵ xy in each case is equal

x and y are inversely proportional

(iii) xy = 9 x 4 = 36

= 3 x 12 = 36

= 6 x 9 = 54

= 36 x 1 = 36

∵ xy in each is not equal

x and y are not inversely proportional

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**Question 2.**

**Solution:**

x and y are inversely proportional

xy is equal

Now,

**Question 3.**

**Solution:**

Let required number of days = x

**Question 4.**

**Solution:**

A pond is! dug in 8 days by = 12 men

It can be dug in 1 day by = 12 x 8 men (Less days, more men)

and it can be dug in 6 days by = \(\\ \frac { 12X8 }{ 6 } \)

= 16 men Ans. (more days, less men)

**Question 5.**

**Solution:**

Let 14 cows can graze in x days

**Question 6.**

**Solution:**

Let required time take = x hour

By inverse proportion

60 : x :: 75 : 5

x = \(\\ \frac { 50X5 }{ 75 } \)

Time required = 4 hours

**Question 7.**

**Solution:**

Let machines required = x

**Question 8.**

**Solution:**

Let 8 taken will fill in tank in x hour

**Question 9.**

**Solution:**

8 taps can fill tank in = 27 minutes

1 tap can fill that tank in = 27 x 8 minutes (less tap, more time)

8 – 2 = 6 taps can fill that tank in

= \(\\ \frac { 27X8 }{ 6 } \) minutes

= 36 minutes

**Question 10.**

**Solution:**

Let total animals can be feed with food in x days

**Question 11.**

**Solution:**

Let for x day, the food provision is sufficient for 900 + 500 = 1400 men

**Question 12.**

**Solution:**

Let the food will be for x days

**Question 13.**

**Solution:**

Let each period will be of x minutes

**Question 14.**

**Solution:**

x and y are inversely

and x = 15, y = 6

Then xy = 15 x 6 = 90

Now if x = 9, then y = \(\\ \frac { 90 }{ 9 } \)

= 10

**Question 15.**

**Solution:**

x and y are inversely and x = 18, y = 8

xy = 18 x 8 = 144

Now if y = 16,

then x = \(\\ \frac { 144 }{ 16 } \)

= 9

Hope given RS Aggarwal Solutions Class 8 Chapter 12 Direct and Inverse Proportions Ex 12B are helpful to complete your math homework.

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