Question

There is a bag with only red marbles and blue marbles.

The probability of randomly choosing a red marble is 4/9.
There are 32 red marbles in the bag and each is equally likely to be chosen.
Work out how many marbles in total there must be.

Answer 1

Explanation:

4/9 = 32 / x

Let x be any marble that is not red and the red ones.

Cross Multiply

4x = 9*32

4x = 288 Divide by 4

x = 288/4

x = 72

So the whole bag contains 72 marbles.