24 litre of alcohol is mixed with 72 litre water. (x) litre of total mixture is taken out and 16 litre alcohol and 24 litre water are added in the mixture. The final mixture contains 30% alcohol, find the value of (x).

Initial mixture has 24L alcohol + 72L water = 96L total (25% alcohol). When x litres of mixture is removed, the proportion remains the same, so 0.25x alcohol and 0.75x water are removed. After adding 16L alcohol and 24L water, final mixture has (40-0.25x) alcohol and (96-0.75x) water. Total volume is (136-x) litres. Given that alcohol is 30% of final mixture: (40-0.25x)/(136-x) = 0.30. Solving gives 0.05x = 0.8, so x = 16 litres.