Question

A jar contains 28 marbles. Half of the marbles are red. Half of the non-red marbles are white and the rest are blue. Todd chose a white marble at random and kept it. What is the probability that when Hosea now draws a marble it will also be white

Answer 1

2/9

Explanation:

28 marbles in all

"Half of the marbles are red."

28/2 = 14 red

"Half of the non-red marbles are white..."

14/2 = 7 white

"...and the rest are blue."

25 -14 -7 = 7 blue

"Todd chose a white marble at random... " -from the bag that has...

14 red 7 white 7 blue

"... and kept it."- so now the marbles left in the jar are...

14 red 6 white 7 blue

P (white) = Number of white marbles/ Total number of marbles = 6/27 = 2/9