The probabilities that a husband and wife will be alive in 15 years time are m and n respectively. Find the probability that only one of them will be alive at that time.
-
A.
mn -
B.
m + n -
C.
m + n – 2mn -
D.
1 – mn
Correct Answer: Option C
Explanation
P(only one alive) = P(husband and not wife) + P(wife and not husband)
= m (1 – n) + n ( 1 – m)
= m – mn + n – mn
= m + n – 2mn