Question is incomplete. Here is the complete question.
A city employee paints curbs iin parking lots and replaces road signs. It takes 0.5 hour to paint a parking lot curb and 2.5 hours to replace a road sign. The function below can be used to find c, the number of parking lot curbs the employee paints when he replaces r road signs in a 40-hour workweek.
[tex]c=\frac{40-2.5r}{0.5}[/tex]
If the employee painted 20 curbs in one week, how many road signs did he replace that week?
a) 20 b) 30 c) 0 d) 12
Answer: d) 12
Step-by-step explanation: In one week, the employee painted 20 curbs.
c is the number of curbs painted in one week, so: c = 20
[tex]20=\frac{40-2.5r}{0.5}[/tex]
[tex]40-2.5r=20*0.5[/tex]
[tex]-2.5r=10-40[/tex]
[tex]-2.5r=-30[/tex]
[tex]r=\frac{-30}{-2.5}[/tex]
r = 12
In one week, the employee replaced 12 road signs.
