In a class there are 20 boys and 25 girls. In how many ways can a boy and a girl be selected?

A. 400
B. 500
C. 600
D. 20
Explanation:
We can select one boy from 20 boys in 20 ways.
We select one girl from 25 girls in 25 ways
We select a boy and girl in 20 * 25 ways i.e., = 500 ways.