How much water, free of cost, should be added to 18 litres of milk worth Rs 70 per litre so that the value of the mixture is Rs 60 per litre?

A2 litres

B3 litres ✓ Correct

C4 litres

D5 litres

Correct answer: (B) 3 litres

Explanation

3 litres of water should be added.

Total value of milk = 18 x 70 = Rs 1260, unchanged by free water.

New volume = 18 + x at Rs 60 per litre.

1260 / (18 + x) = 60, so 18 + x = 21.

x = 3 litres.

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