Question

A bag contains 99 marbles, some white and some red. The ratio of white marbles to red ones is 5:4. how many white marbles are there?

Answer 1

55 white

Explanation:

So ratio 5:4 is essentially saying, for each 5 white marbles, there are 4 red ones. This can be represented in the equation: 5x+4x=99. We specifically want an integer solution. Because what is 1.2 of a marble? And what is -1 marbles? So as x increases by 1, the entire thing increases by 9. This gives you the equation: 9x=99 which gives you x=11. So there are 55 white and 44 red.