Given that:
Cost of the new plumbing fixtures = $160
Labor charge per hour = $50
Let x denotes the number of hours of labor. Then,
[tex]\begin{gathered} \text{Cost of repair = Cost of the new plumbing fixtures+Labor charge per } \\ \text{hour}\cdot Number\text{ of hours of labor} \\ C=160+50x \end{gathered}[/tex]It represents the required relation.