Question

Two mechanics worked on a car. the first mechanic worked for 5 hours, and the second mechanic worked for 15 hours. together they charged a total of $1925 . what was the rate charged per hour by each mechanic if the sum of the two rates was $205 per hour?

Answer 1

Let x and y represent the hourly rates of the first and second mechanics, respectively.
.. x + y = 205 . . . . . . . the sum of the two rates was $205 per hour
.. 5x +15y = 1925 . . . . they charged a total of $1925

Divide the second equation by 5, then subtract the first equation.
.. x +3y = 385
.. (x +3y) -(x +y) = (385) -(205)
.. 2y = 180
.. y = 90
.. x = 205 -y = 115

The first mechanic charged $115 per hour; the second charged $90 per hour.