Question

There are 5 doors to a lecture room. The number of ways that a student can enter the room and leave it by a different door is 20.

• A. 20
• B. 16

Answer 1

The correct option is A 20

A student can enter the room in 5 ways but he can leave the room in 4 ways.
So, the total number of ways in which this can be done = 5 $\times$ 4 = 20