Question

A mixture of 60 litres contains milk and water in the ratio 7: 3. How
water must he added to it so that the ratio of milk to water may be 3:7?​

Answer 1

Answer:

80 litres

Step-by-step explanation:

Milk : Water = 7 : 3

Total number of units = 7 + 3 = 10 units

Total amount of mixture = 60 litres

Find the amount of milk:

10 units = 60 litres

1 unit = 60 ÷ 10 = 6 litres

7 units = 6 x 7 = 42 litres

Find the amount of water:

1 unit = 6 litres

3 units = 6 x 3 = 18 litres

To change to the ratio to 3 : 7

⇒ the number of units for milk now is 3

Find the amount of water needed:

3 units = 42 litres

1 unit = 42 ÷ 3 = 14 litres

7 units = 14 x 7 = 98 litres

Find the amount of water to be added:

Water to be added = 98 - 18 = 80 litres

Answer: 80 litres of water