Question

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

The probability of randomly choosing a red marble is 2/7







There are 16 red marbles in the bag and each is equally likely to be chosen.

Work out how many marbles in total there must be.

Answer 1

Answer: 56

Explanation:

Given that :

Marbles in bag are only red and blue ;

Probability of randomly choosing a red = 2/7

Number of red marbles in bag = 16

The total Number of marbles =?

P(choosing a red marble) = required outcome / Total possible outcomes

Required outcome = number of red marbles

Total possible outcomes = total number of blue and red marbles

Total number of blue and red marbles = x

P(choosing a red marble) = required outcome / Total possible outcomes

2/7 = 16 / x

Cross multiply

2x = 16 * 7

2x = 112

x = 112 / 2

x = 56 marbles

Total number of marbles = 56