For the sample space A B C D we are told that PA 025 PB 03

For the sample space (A, B, C, D) we are told that P(A) = 0.25, P(B) = 0.30 P(C) = 0.40. Find P(D).

Solution

Sum of probabilites of all the outcomes of a sample space must be equal to 1. So following must be true:

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

0.25+0.30+0.40+P(D)=1

0.95+P(D)=1

P(D)=0.05