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 $2525

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
$2525
. What was the rate charged per hour by each mechanic if the sum of the two rates was
$140
per hour?

Answer 1

This is a two equations with two unknows type problem.   If the first mechanic's rate is r1 and the second is r2,  the equations are

 

r1 + r2 =  140   and

 

20 r1 + 15 r2 = 2525

 

This set of equations can be solved via the method of substitution.  

The result is  r1 = 85 and r2 = 55