xailer

04-18-2006, 12:32 PM

1. P(A|B) = 7/10, P(B|A) = 7/15, P(A U B) = 3/5

Find P(A n B) and P(A' n B)

2. We put 4 coins X and 2 coins Y randomly in a row. What is probability that one of X coins will be at the beginning and also end of the row? Result should be 3/14

Number of outcomes is 6!

Number of outcomes where X coins are at the beginning and the end of the row is (4! / 2! * 4!)

So result should be (4! / 2! * 4!) / 6! But it is not.

thank you

Find P(A n B) and P(A' n B)

2. We put 4 coins X and 2 coins Y randomly in a row. What is probability that one of X coins will be at the beginning and also end of the row? Result should be 3/14

Number of outcomes is 6!

Number of outcomes where X coins are at the beginning and the end of the row is (4! / 2! * 4!)

So result should be (4! / 2! * 4!) / 6! But it is not.

thank you