The average age of three people is 25. If two of the people are 22, how old is the third person ... ?

A. 23

B. 25

C. 28

D. 31

E. None correct

D. 31

To find the average, we must add all the numbers up and then divide by the amount of numbers there.

Here we have 3 numbers, which two values are given and the average.

So average A, is found by adding all number then dividing by the number of numbers added.

Let's say the average, 25 = 22+22+x/3

Combine like terms, so 25=44+x/3

Then to cancel out the three on the left we must multiply 3 on both sides. 3•25=44+x/3•3

Simplify the equation into

75=44+x

Now we subtract 44 from both sides to move it over to the left, so we can isolate the variable.

75-44=44+x-44

Simplify

31=x

The third person is D. 31