What is the fourth number?

Question

Three of four numbers have a sum of 22. If the average of
the four numbers is 8, what is the fourth number?

Please explain the steps to solving this problem
Thank you.

Answer 1

Let x = the fourth number

To find an average, you add all the number and divide by the amount of numbers you added together.

22 + x = 22         Multiply both sides by 4.

      4

22 + x = 88      Subtract 22 from both sides.

x = 66