## 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

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

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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