Answer:
Option B. [tex]C = 60t + 70[/tex]
Step-by-step explanation:
Given:
The total cost of hiring Beth's Plumber services is expressed as:
[tex]C = 50t + 70[/tex]
Here, the coefficient of [tex]t[/tex] represents the rate per hour and the constant term represents the initial charge.
So, when the rate per hour changes from 50 to 60, this means the coefficient of [tex]t[/tex] changes from 50 to 60. But, there is no change in the initial charge. So, 70 remains the same as the original equation.
∴ New equation is given as:
[tex]C = 60t + 70[/tex]
Hence, option B is correct.