Question

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

The probability of randomly choosing a red marble is 8/9.
There are 63 marbles in total in the bag and each is equally likely to be chosen.
Work out how many red marbles there must be.​

Answer 1

If the probability of picking a red marble out of the total 63 is 8/9, then it's reasonable to think that 8/9 of the total number of marbles must be red. So there are likely 8/9 × 63 = 56 red marbles in the bag.