Question

14. If P(A) = 0.4 and P(B) = 0.5 and P(A and B) = 0.2, then P(B|A) =

a. 0.80. b. 0.50. c. 0.10 d. 0.40. e. none of the above.
15. If P(A) = 0.4 and P(B) = 0.5 and P(A and B) = 0.2, then P(A or B) =
a. 0.7. %3D %3D b. 0.9 c. 1.1. d. 0.2. e. none of the above.

Answer 1

14) b) P(B/A) = 0.50

15) P(A or B) = 0.7

Explanation:

14)

Given P(A) = 0.4 and P(B) = 0.5 and P(A and B) = 0.2

Conditional probability of B given that A

`P((B)/(A) ) = (P(AnB))/(P(A)) = (0.2)/(0.4) = 0.50`

15)

By using Addition theorem on probability

P( A ∪ B) = P(A) + P(B) - P(A∩B)

= 0.4 +0.5 - 0.2

P( A ∪ B) =0.7