Question

Given that P(A and B) = 0.20 and P(A|B) = 0.40, what must the P(B) = ?

a. 0.1
b. 0.2
c. 0.4
d. 0.5

Answer 1

The value of P(B) = 0.5

Explanation:

Given:

Value of P(A and B) = 0.20

Value of P(A|B) = 0.40

Find:

The value of P(B)

Computation:

P(A and B) = P(A|B) x P(B)

By putting value of P(A and B) and P(A|B)

⇒ 0.20 = 0.40 x P(B)

⇒ The value of P(B) = 0.20 / 0.40

⇒ The value of P(B) = 20 / 40

⇒ The value of P(B) = 1 / 2

The value of P(B) = 0.5