Let's call x1: The rate per hour of the number one mechanic. X2: The rate per hour of mechanic number two. The first thing you should do is identify the system of equations that best describes the problem. In this case it is a system of 2 equations with two unknowns which when solved gives a total of x1 = 85 $ / h and x2 = 50 $ / h. Attached solution.
2x=y where 2 is dollars per tomatoe, x is amount of pounds of tomatoes, and y is amount of money spent in total. say you got 3 pounds of tomatoes; the equation would be 2(3)=y. y=6. Hope I helped!