SOLUTION: If Joe gets 97 on his next math quiz, his average will be 90. If he gets 73, his average will be 87. How many quizzes has Joe already taken?

Question 986041: If Joe gets 97 on his next math quiz, his average will be 90. If he gets 73, his average will be 87. How many quizzes has Joe already taken?

Answer by Boreal(15235) (Show Source): You can put this solution on YOUR website!
The difference between the two test scores is 24. The difference between the two averages is 3. That would be 8 tests. Why?
average=total/n
If the total increases by 24, it is still divided by the number of tests to get the average. If the average is increased by 3, there has to be 24/3.
Check:
8 tests*90=720
At the moment, he has 623.
If that is the case, 623+73=696
696/8=87

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