The mean age of 5 people in a room is 32 years. A person enters the room. The mean age is now 40. Wh

The mean age of 5 people in a room is 32 years. A person enters the room. The mean age is now 40. What is the age of the person who entered the room?

Mean = Sum of Ages in Years / Number of People
32 = Sum of Ages in Years / 5

Cross multiply:
Sum of Ages in Years = 32 * 5
Sum of Ages in Years = 160

Calculate new mean after the next person enters the room.
New Mean = (Sum of Ages in Years + New person's age) / (5 + 1)

Given a new Mean of 40, we have:
40 = (160 + New person's age) / 6

Cross multiply:

New Person's Age + 160 = 40 * 6
New Person's Age + 160 = 240

Let the new person's age be n. We have:
n + 160 = 240

To solve for n, we type this equation into our search engine and we get:
n = 80