Averages and Rounding:

When deciding the score value of a diamond, the respective weights of its qualities are: Brilliance 5, Size 4, Color 2, Clarity 2, Cut 1. What is a diamond's quality score if its qualities were as follows? Brilliance 94, Size 82, Color 78, Clarity 91, Cut 96.

This is a question I got on my online practice ACT test and I told me the correct answer is 88, but I don't know why. I really don't even know where to begin to figure this question out, so please help/walk me through it. Thanks!

Question

Averages and Rounding:

When deciding the score value of a diamond, the respective weights of its qualities are: Brilliance 5, Size 4, Color 2, Clarity 2, Cut 1. What is a diamond's quality score if its qualities were as follows? Brilliance 94, Size 82, Color 78, Clarity 91, Cut 96.

This is a question I got on my online practice ACT test and I told me the correct answer is 88, but I don't know why. I really don't even know where to begin to figure this question out, so please help/walk me through it. Thanks!