Question

A box contain 20 balls bearing number 1,2,3,4........20. A ball is drawn at random, from the box. What is the probability that the number on the ball is divisible by 7 ?

Answer 1

Answer:

S = {1,2,3,4,......... ,20}

n(S) = 20

Event A =Number on the ball is divisible by 7

A = {7, 14}

n(A) = 2

p(A) = n(A)/n(S) = 2/20 = 1/10

therefore P(A) = 1/10