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Problem

A student has an average score of 85% after completing four tests.

What is the lowest possible percentage score in any one of the tests?

Solution

If the average score after four tests is 85, the total of all four test scores must be 85 4 = 340. As the maximum score in any one test would be 100, we shall assume that they scored 100 in three tests, making a total of 300.

Hence the minimum score in any one test could be 340 300 = 40%.

What would the student need to score on the next test to take the average to 90%?