Mechanics Hours 9Aa91A
1. **State the problem:** Two mechanics worked on a car. The first mechanic charges 115 per hour, the second charges 80 per hour. Together, they worked 20 hours and charged a total of 1775. We need to find how many hours each mechanic worked.
2. **Define variables:** Let $x$ be the hours worked by the first mechanic, and $y$ be the hours worked by the second mechanic.
3. **Write the system of equations:**
- Total hours: $$x + y = 20$$
- Total charge: $$115x + 80y = 1775$$
4. **Solve the system:** From the first equation, express $y$ as $$y = 20 - x$$
5. Substitute into the second equation:
$$115x + 80(20 - x) = 1775$$
6. Simplify:
$$115x + 1600 - 80x = 1775$$
$$35x + 1600 = 1775$$
7. Subtract 1600 from both sides:
$$35x = 175$$
8. Divide both sides by 35:
$$x = \frac{175}{35} = 5$$
9. Find $y$:
$$y = 20 - 5 = 15$$
10. **Answer:** The first mechanic worked 5 hours, and the second mechanic worked 15 hours.