# A course has 2 sections, Section A and Section B. On the last exam, Section A's 10 students had an average score of 80, and Section B's 20 students had an average score of 90. What is the course average score on that exam?

##### 1 Answer

Feb 1, 2015

You can't just take the mean. It has to a **weighed mean.**

First back to basics:

Section

Section

Total score for

The average score:

**Extra:**

The other way is to realise that

So we **weigh** the average for section

Total average=

Just pick the method that works for you.