
Amanda K. answered 11/08/21
Certified and Experienced Elementary and Special Education Teacher
Leah's average for the past three quizzes is 84. What must she make on the fourth quiz to increase her average to 88?
For this problem, we need to perform multiple steps. The first would be to multiply the average on the first 3 test scores by 3 to get the total number of points she scored on the three tests total.
Then we need to assign a variable for the unknown test score. I like to use x because it's easy to remember.
So to find the average, remember we need to take the sum of all the numbers we have and divide it by the total number of items in the set. In this case, we would say (the total number of points on the first 3 tests +x) divided by the total number of tests (4) is equal to 88.