In a textbook on mathematics there are three exercises A, B and C consisting of 12, 18 and 10 questions respectively. In how many ways can three questions be selected choosing one from each exercise?
Given: three exercises A, B and C consisting of 12, 18 and 10 questions respectively.
To find: number of ways in which three questions be selected choosing one from each exercise.
Ways of selecting one question from exercise A:12C1 (way of selecting one element from n number of elements.)
Ways of selecting one question from exercise B:18C1
Ways of selecting one question from exercise C:10C1
So number of ways of choosing one question from each exercise A ,B,C =12C1 × 18C1 × 10C1
=12 × 18 × 10
=2160