A Mathsy question about averages.

[covey]

Ok, You have a table like this:

AsBsCs
5320
23200

You want to know the average percentage of As and Bs to Cs(that is: (As + Bs)/Cs )
Is it correct to:

1. Add up all the As, add up all the Bs, add up all the Cs, then find the percentile: 5+2=7, 3+3=6, 20+200=220, percent = 13/220 =5.9%ish
2. Work out the two percentages, then average them: percent1 = 8/20, percent2=5/200, average=85/400 = 21%ish.

And what, oh what is the semantic difference between these two numbers? What do they both mean? They must both mean something!

Does that make sense?
Covey.