The following are the ages (years) of 5 people in a room:

20, 21, 13, 22, 18

A person enters the room.

The mean age of the 6 people is now 18.

What is the age of the person who entered the room?

The person is 14 years old

Step-by-step explanation:

1. Multiply 6 times 18 which is 108

2. Add all numbers together in list which is 94

3. Subtract 94 from 108 which is 14

4. To check answer add 94 plus 14 and divide by 6 and you will get the median which is 18, now you know this answer is correct.