Question 990417: Jake's average score on the first for math tests is 83. On his first test he scored a 72 and his second test he scored an 81. On his fourth test he scored on more point then he did on his third test. What was the score of Jake's fourth math test?
Answer by Cromlix(4381)   (Show Source):
You can put this solution on YOUR website! Hi there,
Make his third test = 'x'
Fourth test then = x + 1
So adding up the 4 tests
(83 + 72 + x + (x + 1))/4 = 83
Totalling up.
(2x + 156)/4 = 83
(2x + 156) = 83 x 4
2x + 156 = 332
2x = 332 - 156
2x = 176
x = 88
4 scores are:
83,72,88,89.
So, fourth score was 89.
Hope this helps :-)
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