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.
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.
