Question

If 3a +5b =10 and 5a +3b =30 what is the average of a and b?

Answer 1

Hello, please consider the following.

`3a+5b + 5a + 3b = 8(a+b)=10+30=40\\\\a+b=(40)/(8)=5`

And the average is

`(a+b)/(2)\boxed{=(5)/(2)}`

Thank you.