Assume that A and B are events in a sample space and that P(A) = .40 and P(B|A) = .25. How do you find P(A intersection B)?
1 Answer
Feb 24, 2017
# P( A nn B) = 0.1#
Explanation:
We use the definition of conditional probability:
#P(A|B) = (P( A nn B)) / (P(B))#
So swapping the roles of
# P(B|A) = (P( B nn A)) / (P(A))#
We are given that
# 0.25 = (P( A nn B)) / 0.40 => P( A nn B) = 0.25 * 0.40 = 0.1#