Concerning two events A and B, the following probabilities are specified:

Question

Concerning two events A and B, the following probabilities are specified:

P(A) = .4. P(B) = .3, and P(A [ B) the symbol here between A and B is the union symbol that looks like a u. = .6. What is the probability that“

A occurs and B does not occur”?

Answer 1

The probability is simply P(A)-P(A and B).    As you know, P(A)+P(B)-P(A and B)= P(A U B). So rearrange the formula, you get P(A)-P(A and B)=P(A U B)-P(B). You have all the numbers, just plug in and you will find the probability of A but not B

Answer 2

OK, Julie, let's see what we can do here.

 

The probability that A occurs and B does not occur, P(A AND B'), is P(A U B) - P(B), so .6 - .3 = .3

 

Hope this helps!