An electrician charges $60 as a one-time fee plus an additional $55 per hour. If the total bill is $252.50, how many hours did it take for the electrician to complete the repair? Part A: Define the variable for this problem. (5 pts)

7 answers

Part A:

Let \( h \) represent the number of hours the electrician worked.

Now the total cost can be expressed with the following equation based on the given charges:

Total bill = One-time fee + (Hourly rate × Number of hours) \[ \text{Total bill} = 60 + 55h \]

In this problem, the total bill is $252.50, so we can write the equation as: \[ 252.50 = 60 + 55h \]

Thus, the variable defined for this problem is \( h \), the number of hours worked by the electrician.

Part B: Write an equation with the variable to represent the situation. (5 pts)

Part B:

Based on the situation described, the equation that represents the total bill for the electrician's services can be written as:

\[ 252.50 = 60 + 55h \]

In this equation:

  • \( 252.50 \) is the total bill,
  • \( 60 \) is the one-time fee,
  • \( 55 \) is the hourly rate (cost per hour),
  • \( h \) represents the number of hours worked by the electrician.
Part C: Solve the equation using inverse operations. Show ALL work

Part C:

To solve the equation \( 252.50 = 60 + 55h \) using inverse operations, we will isolate the variable \( h \). Here are the steps:

  1. Subtract 60 from both sides of the equation to eliminate the one-time fee:

    \[ 252.50 - 60 = 55h \]

    Simplifying the left side:

    \[ 192.50 = 55h \]

  2. Divide both sides by 55 to solve for \( h \):

    \[ h = \frac{192.50}{55} \]

    Now, performing the division:

    \[ h = 3.5 \]

So, the solution is:

\[ h = 3.5 \]

This means it took the electrician 3.5 hours to complete the repair.

Part D: If he arrived at 10:30 a.m., what time was he finished with the repair? Show calculations. (5 pts)

Part D:

The electrician worked for 3.5 hours, starting at 10:30 a.m. To determine what time he finished, we can break it down into two parts: 3 hours and 30 minutes.

  1. Adding 3 hours to 10:30 a.m.:

    \[ 10:30 , \text{a.m.} + 3 , \text{hours} = 1:30 , \text{p.m.} \]

  2. Adding 30 minutes to 1:30 p.m.:

    \[ 1:30 , \text{p.m.} + 30 , \text{minutes} = 2:00 , \text{p.m.} \]

So, the electrician finished with the repair at 2:00 p.m.