Question

Mrs. Bergstedt found the mean of her 15 Algebra II students' latest test scores. It was 85. She thought this was exceptional and slightly skewed by Jill's grade, so she removed her test grade and found that the new mean was 84.
What was Jills Grade?

Answer 1

So the average on the exam was an 85, and there are 15 students in the class. Can you tell me how many total points the class earned on the exam? (If you add everyone's score together?)

Answer 2

that all the info i was given so the only thing i know to do is to multiply 85 by 15...

Answer 3

Right :)

Answer 4

You don't need the individual test scores for that step, the mean means that you added all the scores up and divided them by the number of students. Multiplying the average by the number of students give you the total score again.

Ok, so 15x85=1275. Now what if we take Jill's grade out? How do you think that might change the average?

Answer 5

it would lower it obviously. do you just subtract the answers it might be and find the mean again?

Answer 6

What do you mean "subtract the answers"? You will have to subtract, I just want to make sure I understand what you're doing.

Answer 7

its multiple choice. and the possible answers are 84 85 98 99

Answer 8

That's one way of doing it, but let's pretend it wasn't multiple choice. With Jill's score the class gets 1275 points. Without it the average is 84. Now there are only 14 tests being averaged, so the new "class total" is 1176. Jill's score is the difference between the class's scores

Answer 9

thanks i figured it out.

Answer 10

Good job