If a number is selected at random from each of the sets p = {1, 2, 3} and Q = {2, 3, 5}, find the probability that the sum of the numbers is prime
-
A.
(frac{5}{9}) -
B.
1(frac{4}{9}) -
C.
(frac{1}{3}) -
D.
(frac{2}{9})
Correct Answer: Option C
Explanation
p = { 1, 2, 3}
Q = {2, 3, 5}
prob(prime number) = prob(1 and 2) or
= prob(2 and 3) or
= prob(3 and 2)
There are three possibilities of the sum being prime
Total possibility = 9
probability(sum being prime) = (frac{3}{9})
= (frac{1}{3})