Suppose you have a bag of red, blue, and yellow marbles. If the probability of picking a red marble is1/6 and the probability of picking a yellow marble is 1/2, what is the probability of picking a blue marble?

1. 1/4

2.1/3

3.2/3

4.1/8

The probabilities of picking a red, blue, and yellow marble must be equal to 1. so

P (R) + P (Y) + P (B) = 1

1/6+1/2+P (B) = 1 making all terms have a common denominator of 6 we have:

1+3+6P (B) = 6

4+6P (B) = 6

6P (B) = 2

P (B) = 2/6

P (B) = 1/3