Question

if A and B as shown below are two mutally exclusive events, what P(A or B)?
P(A)=1/8,P(B)=2/5

Answer 1

A or B - either one happens

Answer 2

the possible choices are 21/40, 3/20, 3/13, and 1/20

Answer 3

So this is the defenition --

Answer 4

what do you mean? @DanJS

Answer 5

Rule of Addition The probability that Event A or Event B occurs is equal to the probability that Event A occurs plus the probability that Event B occurs minus the probability that both Events A and B occur.
P(A ∪ B) = P(A) + P(B) - P(A ∩ B))

Note: Invoking the fact that P(A ∩ B) = P( A )P( B | A ), the Addition Rule can also be expressed as
P(A ∪ B) = P(A) + P(B) - P(A)P( B | A )