mechanic rates per hour

Question

Two mechanics worked on a car. The first mechanic worked for 20 hours, and the second mechanic worked for 15 hours. Together they charged a total of $3450. What was the rate charged per hour by each mechanic if the sum of the two rates was $195 per hour?

Answer 1

Let rate of first is $x per hour., then rate of second is $(195 - x) per hour.

We get equation: 20x + 15(195 - x) = 3450, 20x + 2925 -15x = 3450, 5x = 525; x = 105, 195 - x = 195 - 105 = 90.

Answer: rate of 1st mechanic is $105 per hour; rate of 2nd mechanic is $90 per hour