SOLUTION: I want to score 80% in a class, the first 3 tests scores are 71, 82, and 90. What is the lowest score I can get on the 4th test? I need to know how to set this problem up to solve

Algebra ->  Average -> SOLUTION: I want to score 80% in a class, the first 3 tests scores are 71, 82, and 90. What is the lowest score I can get on the 4th test? I need to know how to set this problem up to solve      Log On


   

Question 794879: I want to score 80% in a class, the first 3 tests scores are 71, 82, and 90. What is the lowest score I can get on the 4th test? I need to know how to set this problem up to solve.
Answer by rfer(16322) About Me  (Show Source):
You can put this solution on YOUR website!
(71+82+90+x)/4=80
243+x=80*4
x=320-243
x=77%