Question

A natural number is chosen at random from among the first 300. What Is the probability that the number so chosen is divisible by 3 or 5. Select the correct answer from above options

Answer 1

n(S) = 300 Let A: Number is divisible by 3 = (3, 6, 9 300) ∴ n(A) = 100 Let B: Number is divisible by 5 = (5, 10 300) ∴ n(B) = 60 A∩ B: Number is divisible by 3 & 5 i.e., 15 A∩B = {15 ………………….300} n(A∩B) = 300 15 = 20 300