Question

The average age of 15 people in a group is 24 years old. Then, when one person grew, the average was 23. If so, how old is the new person?

Answer 1

Before the new person came, we had,

Age of all persons÷Number of persons=24

Lets say that the previous number of people was 'x'.

Then,

x/15=24

So, x=360

Now, after one more person came,

The number of people became 16.

The total age would become 360+y,

where y is the age of new person.

So, according to the question,

(360+y)÷16=23

360+y=368

y=8

So, the age of new person is 8 years.