Question

A bag contains 5 blue marbles, 2 green marbles, and 3 yellow marbles. What is the probability of choosing one green marble and then a yellow marble with replacement? 3/50 1/15 1/2 6/10

Answer 1

Explanation:

Total number of marbles = 5 + 2 + 3 = 10

Probability of choosing 1 green marble = 2/10

Probability of choosing 1 yellow marble = 3/10

Notice (and this is important) that the denominator didn't change. Why?

Because you replaced the first marble into the bag. That word replacement is critical in a problem of this nature. There is the term non replacement which means that the second draw would have a denominator of 9.

So what is the probability of P(green then yellow)?

P(green then yellow) = 3/10 * 2/10 = 6/100

Answer: P(green then yellow) = 3/50 because 6 / 100 reduces.