Question

There is a bag with only red marbles and blue marbles. The probability of randomly choosing a red marble is 11/12. There are 84 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

77

Explanation:

If the probability of choosing a red marble is 11/12, then 11/12 of the marbles in the bag must be red. Therefore, the number of red marbles is 84*11/12=7*11=77 marbles. Hope this helps!