Multiple choice

A container originally contains 10 litres of pure spirit. From this container, 1 litre of spirit is replaced with 1 litre of water. Subsequently, 1 litre of the mixture is again replaced with 1 litre of water and this process is repeated one more time. How much spirit is now left in the container?

  1. 7.58 litres

  2. 7.84 litres

  3. 7 litres

  4. 7.29 litres

Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The amount of spirit remaining after n replacements is given by the formula: Final = Initial * (1 - volume_replaced/total_volume)^n. Here, 10 * (1 - 1/10)^3 = 10 * (0.9)^3 = 10 * 0.729 = 7.29 litres.