Math
posted by Sabina on .
In exercises 1 and 2, use the following information. You randomly draw letter tiles from a bag containing the letters from the word PROBABILITIES.
1. You randomly select a B. You replace it. Then you choose a T. Tell whether the events are independent or dependent. Then find the probability that both events occur.
2. You randomly pick an I. Then without replacing the first I, you pick another I. Tell whether the events are independent or dependent. Then find the probability that both events occur.
I know that the first one is independent, and the second is dependent. But I don't get how to solve the second part. PLEASE help! Thanks..

in the first, the prob of getting the B is 2/13, replacing that and then picking a T has a prob of 1/13
so the prob of picking a B, followed by the T is
(2/13)(1/13) = 2/169
in the second you are not replacing the letter so for the second prob. there are only 12 letters left
so Prob. of an I, then the second I is (3/13)(2/12) = 1/26