A vessel is filled with liquid, 3 parts of which are water and 5 parts syrup. How much of the mixture must be drawn off and replaced with water so that the mixture may be half water and half syrup?
Answer: Option C
Suppose the vessel initially contains 8 litres of liquid.
Let x litres of this liquid be replaced with water.
5x + 24 = 40 - 5x
10x = 16