In a class there are 15 boy and 12 girls. The teacher wants to select 1 boy and 1 girl to represent the class for a function. In how many ways can the teacher make the selection?

Explanation

Here the teacher is to perform two operations:
(i) selecting 1 boy out of 15 boys,
and (ii) selecting 1 girl out of 12 girls.
The first of these can be done in 15 ways and the second in 12 ways.
So, by the fundamental principle of multiplication, the required number of ways `=(15xx12)=180.`
Hence, the teacher can make the selection of 1 boy and 1 girl in 180 ways.