Given : two mechanics worked on a car
The first : worked for 5 hours
The second : worked for 15 hours
Total charge for both = $1,225
Let the charge rate per hour for the first is x and for the second is y
So,
[tex]5x+15y=1225[/tex]the sum of the two rates was $125 per hour so,
[tex]x+y=125[/tex]so, we have the following system of equations :
[tex]\begin{gathered} 5x+15y=1225 \\ x+y=125 \end{gathered}[/tex]Form the second equation : y = 125 - x
Substitute at the first equation with y to find the value of x
so,
[tex]\begin{gathered} 5x+15\cdot(125-x)=1225 \\ 5x+1875-15x=1225 \\ 5x-15x=1225-1875 \\ -10x=-650 \\ \\ x=\frac{-650}{-10}=65 \\ \\ y=125-x=125-65=60 \end{gathered}[/tex]so, the rate of the first one who worked 5 hours = $65 per hour
And the rate of the second will be = $60 per hour