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.
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!
