Milk and water concept

**Problem 1:** A mixture of 40 lit of milk and water contains 10% water. How much water should be added so water may 20% in the mixture

Solution: Quantity of mixture = 40 lit.

Percentage of water = 10%

The quantity of water = lit

The quantity of milk = 40-4=36

How much water should be added so water maybe 20% in the new mixture

x=5

Shortcut :

Water Milk Water Milk

10 : 90 1 : 9

20 : 80 1 : 4

To equate the milk multiply (1:9) with 4 and (1:4) with 9

Water Milk Water Milk

( 1 : 9 ) *4 4 : 36

( 1 : 4 ) *9 9 : 36

4-9=5

5 40

40 ? (36+4=40)

**Problem 2:** Fresh fruit contains 68% water and dry fruit contains 20% water. How many kgs of dry fruits can be made from 75kg of fresh fruit?

Solution :

Water pulp Water pulp

Fresh 68% : 32% 17 : 8

Dry 20% : 80% 2 : 8

17+8=25 2+8=10

25% 75

10% ?

Problem 3: A solution of salt water contains 20% salt by weight. If 20lit of water is evaporated from the solution, the solution contains 25% of salt. What is the original quantity of solution?

Solution:

Salt Water Salt Water

20% : 80% 1 : 4

25% : 75% 1 : 3

1+4=5 1+3=4

5-4=1

1 20lit

5 ?