The sample space of an experiment is { A, B, C, D} and P(A) = 0.1, P(B) = 0.3, P(C) = 0.4. P(D) =

Question

a. 0.3

b. 0.4

c. 0

d. 0.2

Answer 1

The sum of probabilities in a sample  is always equal to 1 .

P(A) + P(B) + P(C) + P(D) = 1

0.1 + 0.3  + 0.4 + P(D) = 1

0.8 + P(D) = 1

P(D) = 1 - 0.8 

P(D) = 0.2 

Option (d) is the correct answer.