Question

A pot contains 81 litres of pure milk. 1/3 of the milk is replaced by the same amount of water. Again 1/3 of the mixture is replaced by that amount of water. The ratio of milk and water in the new mixture is ?​

Answer 1

Answer:

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Initially, Milk = 81 litres and Water = 0 litre.

After 1st operation,

Milk = (81 – 1/3 × 81) litres

= (81 – 27) litres

= 54 litres

Water = (0 + 1/3 × 81) litres

= 27 litres

After 2nd operation,

Milk = (54 – 1/3 × 54) litres

= (54 – 18) litres

Water = (27 – 1/3 × 27) litres + (1/3 × 54 + 1/3 × 27) litres

= (27 – 9) litres + (18 + 9) litres

= 45 litres

Therefore required ratio of milk and water in the new mixture = 36 : 45 = 4 : 5.