Two mechanics worked on a car. The first mechanic worked for 10 hours, and the second mechanic worked for 5 hours. Together they charged a total of $1200. What was the rate charged per hour by each mechanic if the sum of the two rates was $165 per hour?

Step-by-step explanation:

Let a represent the charges made hourly by Mechanic 1 and b represent that of Mechanic 2;

a + b = 165, a = 165 - b

10a + 5b = 1200

substitute the value of a in the second equation;

10 (165 - b) + 5b = 1200

1650 - 10b + 5b = 1200

1650 - 5b = 1200

-5b = 1200 - 1650

-5b = - 450

b = 450/5

b = $90/hr

If mechanic 2 charged $90/hr,

a + 90 = 165

a = 165 - 90

a = $75/hr being the hourly rate charged by mechanic 1.