JAMB - Mathematics (2000 - No. 29)
X and Y are two events. The probability of X or Y is 0.7 and that of X is 0.4. If X and Y are independent, find the probability of Y.
0.30
0.50
0.57
1.80
Forklaring
P (X or Y) = P(X) + P(Y), when they are independent as given.
0.7 = 0.4 + P(Y)
P(Y) = 0.7 - 0.4 = 0.30
0.7 = 0.4 + P(Y)
P(Y) = 0.7 - 0.4 = 0.30