In this question , we have to write an arithmetic expression that calculates the average of 18 and 46.
TO find the average, we have to add the numbers and divide by 2.
So here we have to add 18 and 46 and divide by 2, that is

And that's the required algebraic expression .
6 m.p.g if that's the type of question your referring to...
The answer for this question would be 10
Answer:
see below
Step-by-step explanation:
First determine how much is subtracted from the account
12.57+24.95+36.86 =74.38
They charge .15 per check=3*.15 = .45
Subtract the amounts of the checks and the check fees
139.50-74.38-.45 =64.67