SOLUTION: On the three tests of 100 points each, Takia has an 87 average. What is the lowest score she could earn on the next test to have an 90 average?

Question 507026: On the three tests of 100 points each, Takia has an 87 average. What is the lowest score she could earn on the next test to have an 90 average?
Answer by Earlsdon(6294) (Show Source): You can put this solution on YOUR website!
Let the scores of the first three tests be a, b, and c. Then:
To find the sum of the first three test scores, multiply both sides by 3.
Now let the fourth test score be x, so...
Substitute
Multiply both sides by 4.
Subtract 261.

Takia must score at least 99 points on the fourth test to achieve an overall average of 90.
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