Question

The question is shown in the picture

Answer 1

The equation
service fee + hourly fee = the total fee
20 + 25x = 282.50

Solving the equation
20 + 25x = 282.50
25x = 282.50 - 20
25x = 262.50
x = 262.50/25
x = 10.5
The plumber completes his job in 10.5 hours

The answer is option a.

Answer 2

20 + 25(times the number of hours) = 282.50
You add the 20 because of the one time service fee.

Now lets work this out.
20 + 25x =282.50
25x = 262.50 (subtract both sides by 2 to get the x's alone)
x = 10.5 (divide both sides by 25 to get just x)
x = 10.5 hours

So the answer is A.