A wedding reception bartender is faced with a problem: how many litres of fruit juice must be mixed with 4 litres of 24% flavoured rum to make a sum punch 8% strength?

What do you mean by that I do not Understand

Divide 40%5 and your answer is 8

the law of definite proportions states samples of a compound will always contain the same proportion of elements by mass. in other words, a given compound will always contain the same elements in the same proportions by mass.the law of multiple proportions states when two elements combine with each other to form more than one compound, then the weights of one element that combine with a fixed weight of the other are in a ratio of small whole numbers.