Answer:
Use Plumber B since he charges $215, $10 less than Plumber A.
Explanation:
Let y = total cost, and x = number of hours.
Plumber A:
y = 50x + 25
For a 4-hour call, x = 4.
y = 50(4) + 25
y = 200 + 25
y = 225
Plumber A charges $225 for a 4-hour call.
Plumber B:
y = 35x + 45
For a 4-hour call, x = 4.
y = 45(4) + 35
y = 180 + 35
y = 215
Plumber B charges $215 for a 4-hour call.
Answer: Use Plumber B since he charges $215, $10 less than Plumber A.