SOLUTION: Shauna had an English average of 84%. on her next test she scored 93%, and this raised her overall average to 86%. On the test after this, her average fell to 85%. what was her mar

Algebra ->  Finance -> SOLUTION: Shauna had an English average of 84%. on her next test she scored 93%, and this raised her overall average to 86%. On the test after this, her average fell to 85%. what was her mar      Log On


   

Question 1113586: Shauna had an English average of 84%. on her next test she scored 93%, and this raised her overall average to 86%. On the test after this, her average fell to 85%. what was her mark on the last test?
Answer by greenestamps(13206) About Me  (Show Source):
You can put this solution on YOUR website!


To have a chance of solving the problem, we have to assume (since it is not stated) that all tests have the same weight.

But when we do that, the numbers given in the problem don't allow us to find a solution.

If the average on the first n tests is 84 and the next test is 93, then the sum of all the test scores is 84n+93; if the average after that last test is 86, then the sum of all the test scores is 86(n+1).

But solving the equation 84n+93 = 86(n+1) to find the original number of tests does not give an answer that is a whole number. Obviously the number of tests must be a whole number -- so the problem as stated can't be solved.