SOLUTION: It's been a while! I have 2 known numbers and an average of 3 numbers. The numbers I know are 72 and 73 and the average including the 3rd number is 72.9. Here is my formula and

Algebra ->  Divisibility and Prime Numbers -> SOLUTION: It's been a while! I have 2 known numbers and an average of 3 numbers. The numbers I know are 72 and 73 and the average including the 3rd number is 72.9. Here is my formula and      Log On


   

Question 53800: It's been a while! I have 2 known numbers and an average of 3 numbers. The numbers I know are 72 and 73 and the average including the 3rd number is 72.9. Here is my formula and I'm trying to solve for x:
(72+73+x)/3=72.9.
Answer by funmath(2933) About Me  (Show Source):
You can put this solution on YOUR website!
First simplify the parenthese, then multiply both sides by 3, then subtract 145 from both sides like so:
%2872%2B73%2Bx%29%2F3=72.9
%28145%2Bx%29%2F3=72.9
3%28145%2Bx%29%2F3=3%2872.9%29
%28cross%283%29%29%28145%2Bx%29%2F%28cross%283%29%29=218.7
145%2Bx=218.7
-145%2B145%2Bx=218.7-145
x=73.7
Happy Calculating!