If U = {x : x is an integer and 1 ≤ ≤ x ≤ ≤ 20 E1 = {x : x is a multiple of 3} E2 = {x : x is a multiple of 4} and an integer is picked at random from U, fi...

If U = {x : x is an integer and 1 $\le$ x $\le$ 20
E1 = {x : x is a multiple of 3}
E2 = {x : x is a multiple of 4}
and an integer is picked at random from U, find the probability that it is not in E2

Answer Details

U = {1, 2, 3, 4, 5,..., 20}
E1 = {3, 6, 9, 12, 15, 18}
E2 = {4, 8, 12, 16, 20}
P(E1) = 5/20
P(not E1) = 1 - (5/20) = 15/20 = 3/4