SOLUTION: Joel took two exams. He scored 14 points less on the second test than he did on the first. His average score for the two exams was 84 points. If x= his score on the first test, and

Algebra ->  Average -> SOLUTION: Joel took two exams. He scored 14 points less on the second test than he did on the first. His average score for the two exams was 84 points. If x= his score on the first test, and      Log On


   

Question 999158: Joel took two exams. He scored 14 points less on the second test than he did on the first. His average score for the two exams was 84 points. If x= his score on the first test, and y= his score on the second tests, then the average is given by the formula x+y/2. What did joel score on the second test?
Answer by Theo(13342) About Me  (Show Source):
You can put this solution on YOUR website!
average score is (x+y)/2
he scored 14 points less on the second test than he did on the first.
y = x - 14.
replace y with x-14 to get the average score to be equal to (x + x - 14) / 2 which results in (2x-14)/2
since the average score on both tests is 84, then you get:
(2x-14)/2 = 84
multiply both sides of this equation by 2 to get:
2x-14 = 168
add 14 to both sides of this equation to get:
2x = 182
divide both sides of this equation by 2 to get:
x = 91
he got 91 on the first test.
he got 91 - 14 = 77 on the second test.
(91 + 77) / 2 = 168/2 = 84 average on both tests.
he scored 77 on the second test is your solution.