Question

Three of four numbers have a sum of 22. If the average of
the four numbers is 8, what is the fourth number?
A. 4
B. 6
C. 8
D. 10

Answer 1

-- If the average of 4 numbers is 8, then they must all add up to 32 .

-- If 3 of them add up to 22, then the 4th number is 10 .