Question

The mean age of 5 people in a room is 40 years.

A person enters the room.
The mean age is now 35.
What is the age of the person who entered the room?​

Answer 1

the answer is 40

Answer 2

the person entering the room is 10 years old

Explanation:

x / 5 = 40

x = 40 * 5

x = 200

so the total of all the ages of 5 people is 200

x/ 6 = 35

x = 35 * 6

x = 210

the total of all the ages of 6 people would have to be 210 for there to be a mean age of 35

therefore, a ten year old kid entering the room, will make up the difference