8 litres are drawn from a cask full of wine and is then filled with water. This operation is performed three more times. The ratio of the quantity of wine now left in cask to that of water is 16 : 65. How much wine did the cask hold originally?
Q1. 8 litres are drawn from a cask full of wine and is then filled with water. This operation is performed three more times. The ratio of the quantity of wine now left in cask to that of water is 16 : 65. How much wine did the cask hold originally?
Answer: 24 litres
Explanation: After four operations the wine fraction = (1 − 8/V)⁴ = 16/81. Solving gives (1−8/V) = 2/3, so V = 24 litres.