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

Question

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

Answer 1

Let x = the fourth number

22 + x = 8

      4 

22 + x = 32

x = 10

Answer 2

Hello Renee

 

Let a, b, c and d = the four numbers.

 

Equation 1: the sum of 3 numbers = 22, therefore, this can equate to a + b + c = 22

 

Equation 2:  the average of the 4 numbers = 8 or (a + b + c + d) / 4 = 8

 

Multiply both sides of Equation 2 by 4, you get

 

a + b + c + d = 32

 

Substitute Equation 1 into the above equation, you get

 

22 + d = 32

 

d = 10

 

Therefore, the 4th number is 10.