To find the total hours \( h \) the plumber took to repair the leak, we can use the information given. The plumber charges a flat fee for the visit and an hourly rate:
- The initial visit fee is $65.
- The hourly charge is $75 per hour.
- The total bill is $196.25.
The equation can be set up as:
\[ \text{Total bill} = \text{Visit fee} + (\text{Hourly rate} \times \text{Hours worked}) \]
Plugging in the values, we get:
\[ 196.25 = 65 + 75h \]
To solve for \( h \), we first subtract the visit fee from both sides:
\[ 196.25 - 65 = 75h \]
Calculating the left side gives:
\[ 131.25 = 75h \]
Now, divide both sides by 75 to isolate \( h \):
\[ h = \frac{131.25}{75} \]
Calculating that yields:
\[ h = 1.75 \]
So the plumber worked for \( 1.75 \) hours.
To find the time the plumber finished the repair, we can add \( 1.75 \) hours to the time he arrived at 9:30 p.m.
1.75 hours is equivalent to 1 hour and 45 minutes.
Starting from 9:30 p.m.:
- Adding 1 hour brings us to 10:30 p.m.
- Adding 45 minutes brings us to 11:15 p.m.
Thus, the plumber finished the repair at:
\[ \text{11:15 p.m.} \]
In summary, the equation is:
\[ h = \frac{196.25 - 65}{75} \]
The plumber finished repairing the leak at 11:15 p.m.