Question

In order to qualify for her school's Honor Roll, Janet must have a test average of a 90. As of right now, she has tests of 88, 94, 81, 96 and 82. She has one test left this marking period . What grade must she earn on the last test to qualify for the Honor Roll?

Answer 1

given an average of 90

and the following as her test: 88, 94, 81, 96 and 82

recall that we were told that she has one test left

so lets make X the one test left

therefore, taking average:

88 + 94 + 81 + 96 + 82 + X/6 = 90

lets cross multiply

88 + 94 + 81 + 96 + 82 + X = 90 x 6

adding up the left hand side and multiplying the right hand side

441 + X = 540

collecting like terms,

X = 540 - 441

X = 99

therefore the grade that hse must earn on her last test for to qualify is 99