SOLUTION: the average of 3 numbers is 12. Two of the numbers are 7 and 13. What is the third number?

Algebra ->  Average -> SOLUTION: the average of 3 numbers is 12. Two of the numbers are 7 and 13. What is the third number?      Log On


   

Question 656316: the average of 3 numbers is 12. Two of the numbers are 7 and 13.
What is the third number?
Answer by checkley79(3341) About Me  (Show Source):
You can put this solution on YOUR website!
(7+13+X)/3=12
(20+X)/3=12 CROSS MULTIPLY.
20+X=36
X=36-20
X=16 ANS.
PROOF:
(7+13+16)/3=12
36/3=12
12=12