A technician charges a flat fee of $75 for a service call plus $40 per hour for labor. If a customer's total bill was $235, how many hours did the technician work?
✓ Correct Answer: Option B
Let 'h' be hours worked. The equation is 75 + 40h = 235. Subtract 75 from both sides: 40h = 160. Divide by 40: h = 4 hours.