The probability that event B occurs is 0.4, and the probability that events A and B both occur is 0.25. If the probability that either event A or event B occurs is 0.6, what is the probability that event A will occur?  Choose the correct choice from the following choices.
A) 0.05
B) 0.45
C) 0.15
D) 0.5
E) 0.55

Rationale: "p ( a or b ) = p ( a ) + p ( b ) - p ( a n b ) 0.6 = 0.4 + p ( a ) - 0.25 p ( a ) = 0.45 ans : b"
Answer: B