SOLUTION: Bill's scores on his first four science tests are 80, 90, 84, and 91. What test score must Bill earn on the fifth test so that his average (mean) is exactly 88?

Question 547605: Bill's scores on his first four science tests are 80, 90, 84, and 91. What test score must Bill earn on the fifth test so that his average (mean) is exactly 88?
Answer by Maths68(1474) (Show Source): You can put this solution on YOUR website!
Total Score in first four tests = 80+90+84+91=345
Score in fifth test = x
Total score in five tests = 345+x
Total number of tests = 5
Average in five test = 88

sum of quantities / number of quantities = Average
(345+x)/5 = 88
345+x=88*5
345+x=440
x=440-345
x=95
Brad has to score 95 in fifth test to get an average of 88.

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