Theresa earned scores of 88 points, 84 points, 88 points, and 91 points on four tests. what is the lowest score she can get on the fifth test and still finish with an average score of 90 points?

96 points
97 points
98 points
99 points

Find the lowest score for the average. Let that number = x

There are 5 tests in all

(88 + 84 + 88 + 91 + x)/5 = 90

First, multiply 5 to both sides

(88 + 84 + 88 + 91 + x)/5(5) = 90(5)

88 + 84 + 88 + 91 + x = 450

Next, Combine like terms

351 + x = 450

Next, isolate the x. Subtract 351 from both sides

351 (-351) + x = 450 (-351)

x = 450 - 351

x = 99

99 is your answer

hope this helps

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