ron has scores of 74 and 85 on his first two midterms. what score dose he need on the third midterm so that his average is 84?

Question

ron has scores of 74 and 85 on his first two midterms. what score dose he need on the third midterm so that his average is 84?

Answer 1

The average of 3 numbers is A = (x + y + z) / 3

 

Here we have x = 74, y = 85, and we want the average to be 84.  So 

 

84 = (74 + 85 +z) / 3

 

252 = 159 + z

 

z = 93 is the required score 

 

Answer 2

Hello Janette,

To find the average of three numbers, we shall add them up, and divide by three.  Let 'x' be one of those numbers that we don't know:

(x+74+85)/3=84.

Multiply both sides by 3 to get:

x+74+85=252, which implies

x+159=252, which yields

x=93.

Thank you for the post!