Correct question :
There is a bag with only red marbles and blue marbles. The probability of randomly choosing a red marble is 7 9 . There are 28 red marbles in the bag and each is equally likely to be chosen. Work out how many marbles in total there must be.
Answer:
Total number of marbles = 36
Step-by-step explanation:
Marbles in bag: Red and Blue only
Probability of randomly choosing a red marble = 7/9
Number of red marbles = 28
Total number of marbles in the bag =?
Probability = required outcome / Total possible outcomes
P(red marble) = required outcome (number of red marbles) / Total possible outcomes(total number of marbles
7/9 = 28 / total number of marbles
Total number of marbles * 7/9 = 28
Total number of marbles = 28 ÷ 7/9
Total number of marbles = 28 * (9/7)
= 252 / 7
Total number of marbles = 36
