Question

A bag has 4 red marbles, 12 blue marbles and 6 yellow marbles. What is the probability of picking a yellow marble, replacing it, and then picking a blue marble?

a) 1/18
b) 18/121
c) 15/22
d) 22/131

Answer 1

Probability of picking a yellow marble = no of yellow marbles/total number of mables = 6/(4 + 12 + 6) = 6/22 = 3/11
Probability of picking a blue marble = 12/22 = 6/11

Probability of picking a yellow marble and a blue marble = 3/11 x 6/11 = 18/121