To determine the total hours \( h \) the plumber worked, we can set up an equation based on the pricing structure of the plumber.
The plumber charges:
- $65 for the visit (fixed cost)
- $75 per hour (variable cost depending on the time spent)
The total cost can be expressed as: \[ \text{Total Cost} = \text{Visit Fee} + \text{Hourly Rate} \times \text{Hours Worked} \] Substituting the costs into the equation gives us: \[ 196.25 = 65 + 75h \]
Now, we can solve for \( h \):
- Subtract the visit fee from both sides: \[ 196.25 - 65 = 75h \] \[ 131.25 = 75h \]
- Now, divide both sides by 75 to isolate \( h \): \[ h = \frac{131.25}{75} \] \[ h = 1.75 \]
So, the total hours \( h \) the plumber took to repair the leak is \( 1.75 \) hours.
Next, to find the time the plumber completed the repair, we can calculate how long \( 1.75 \) hours is from the time he arrived.
He arrived at 9:30 p.m. and worked for \( 1.75 \) hours (which is 1 hour and 45 minutes).
Calculating this:
- 1 hour from 9:30 p.m. brings us to 10:30 p.m.
- Then adding 45 minutes to 10:30 p.m. brings us to 11:15 p.m.
Thus, the plumber finished the repair at 11:15 p.m.