A container holds 80 litres of pure milk. 8 litres are taken out and replaced with water, and this is done once more. How much milk is left in the container?
Correct answer D. 64.8 litres
Explanation
Milk left = 80 x (1 - 8/80)^2 = 80 x 0.81 = 64.8 litres. Subtracting 16 litres directly ignores that the second draw contains water.
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