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 the water is 16:65. How much wine did the cask hold originally? (a) 18 litres (b) 24 litres (c) 32 litres (d) 42 litres

Options

A. 10 ltr
B. 20 ltr
C. 30 ltr
D. 40 ltr

Answer

B

Explanation

Let initial quantity be Q, and final quantity be F
`F=Q[1-(8)/(Q)]^4`
`(81)/(625)=(1-(8)/(Q))^4`
`(2)/(5)=1-(8)/(Q)`
`Q=20`