Question

a bag contains two yellow, two blue, and four red marbles. how many blue marbles must be added to the bag to make the probability of drawing a blue marble 1/2? a. 4 b. 5 c. 2 d. 3

Answer 1

a. 4

Explanation:

there are 2 yellow, 2 blue, and 4 red marbles. in total there are 2 + 2 + 4 = 8.

if the probability is 1/2, then there should be added 4 more blue ones.

2 + 4 = 6, and the new total 8 + 4 = 12

6/12 = 1/2