SOLUTION: Eric has scored 69 , 58 , 95 , and 65 on his previous four tests. What score does he need on his next test so that his average (mean) is 69 ? Also, sorry if I put this in the wr

Algebra ->  Rational-functions -> SOLUTION: Eric has scored 69 , 58 , 95 , and 65 on his previous four tests. What score does he need on his next test so that his average (mean) is 69 ? Also, sorry if I put this in the wr      Log On


   



Question 1082658: Eric has scored 69 , 58 , 95 , and 65 on his previous four tests. What score does he need on his next test so that his average (mean) is 69 ?
Also, sorry if I put this in the wrong category, I wasn't sure..

Answer by addingup(3677) About Me  (Show Source):
You can put this solution on YOUR website!
You said it, all you have to do is calculate the average (mean) with one unknown (What score does he need?), solve for the unknown and you're done:
` ` ` ` ` ` ` `
(69 + 58 + 95 + 65 + x)/5 = 69
(287 + x)/5 = 69 multiply both sides times 5. On the right, 5/5 cancel each other.
287 + x = 345 subtract 287 from both sides:
x = 58