Question

What are the variables and equation if Peter’s Lawn Mowing Service charges $10 per job and $0.20 per square yard and he earns $25 for a job?

Answer 1

`$10+$0.20*x=$25`
Where `x` is the number of square yards.

From this we can easily derive the size of the lawn:

Step 1: `-10` on both sides:
`0.2*x=15`

Step 2: divide both sides by `0.2`
`x=75`

Conclusion:
The lawn is 75 square yards .
(don't forget the last part, or you'll get remarks like "75 what?")