10.Thirty students in a chemistry class took a test on which the overall average score was 78. If the average score for 15 of those students was 85, what was the average score for the remaining members of the class?

I know that "average" means dividing, but i'm not sure what to do.

3 answers

78*30 = 2340 total score

85 * 15 = 1275 score for top 15 students

2340 - 1275 = 1065

1065 / 15 = ?
71
Yes.