- #1

mohamed el teir

- 88

- 1

## Homework Statement

suppose we have 9 balls : 2 red, 3 green, 4 yellow. and we draw 2 balls without replacement, the probability that one of them is red and the other is green is : P(R)P(G\R)+P(G)P(R\G) = (2/9)(3/8)+(3/9)(2/8)

i faced a problem in the textbook which says: the probability that a married man watches a show is 0.4, and the prob. that a married woman watched the same show is 0.5, and the prob. the man watches this show given that his wife does is 0.7. what is the probability that a couple watches the show ?

the answer to this problem is the intersection which is P(W)P(M\W) = 0.5*0.7 = 0.35

my question: why didn't we treat this problem like the first one, i mean giving the answer as P(W)P(M\W)+P(M)P(W\M) ?

## Homework Equations

probability of A given B = P(A\B) = P(A∩B) / P(B)

## The Attempt at a Solution

my thinking about the solution contradiction is merged with the problem statement to be relevant