Direct Proportion and Inverse Proportion Class 7 Maths Chapter 9 Practice Set 37 Solutions Maharashtra Board

Direct Proportion and Inverse Proportion Class 7 Maths Chapter 9 Practice Set 37 Solutions Maharashtra Board

Maharashtra state board textbooks

Std 7 Maths Practice Set 37 Solutions Answers

Question 1.
If 7 kg onions cost Rs 140, how much must we pay for 12 kg onions?
Solution:
Let the cost of 12 kg onions be Rs x.
The quantity of onions and their cost are in direct proportion.
∴ 7140=12x
∴ 7x = 12 × 140 ….(Multiplying both sides by 140x)
∴ x = 12×1407
= 240
We must pay Rs 240 for 12 kg onions.

Question 2.
If Rs 600 buy 15 bunches of feed, how many will Rs 1280 buy?
Solution:
Let the bunches of feed bought for Rs 1280 be x.
The quantity of feed bought and their cost are in direct proportion.
∴ 60015=1280x
∴ 600x = 1280 × 15 …. (Multiplying both sides by 15x)
∴ x=1280×15600=32
∴ 32 bunches of feed can be bought for Rs 1280.

Question 3.
For 9 cows, 13 kg 500 g of food supplement are required every day. In the same proportion, how much will be needed for 12 cows?
Solution:
Let the food supplement required for 12 cows be x kg.
The quantity of food supplement required and the number of cows are in direct proportion.
∴ 13kg500gram9=xkg12
∴ 13.59=x12 ….(13 kg 500 gram = 13.5 kg)
∴ 13.5 × 12 = 9x ….(Multiplying both sides by 9 x 12)
∴ 13.5×129=x
∴ x = 18
∴ The food supplement required for 12 cows is 18 kg.

Question 4.
The cost of 12 quintals of soyabean is Rs 36,000. How much will 8 quintals cost?
Solution:
Let the cost of 8 quintals of soyabean be Rs x.
The quantity of soyabeans and their cost are in direct proportion.
∴ 1236000=8x
∴ 12x = 8 × 36000 ….(Multiplying both sides by 36000x)
∴ x=8×3600012=24000
∴ The cost of 8 quintals of soyabean is Rs 24000.

Question 5.
Two mobiles cost Rs 16,000. How much money will be required to buy 13 such mobiles ?
Solution:
Let the cost of 13 mobiles be Rs x.
The quantity of mobiles and their cost are in direct proportion.
∴ 216000=13x
∴ 2x = 13 × 16000 ….(Multiplying both sides by 16000x)
∴ x=13×160002=104000
∴ Rs 104000 will be required to buy 13 mobiles.