Question

Difficulty: EasyLinear Equations in One Variable

A technician charges a one-time fixed diagnostic fee of $35\$35 plus $25\$25 for each hour of repair work. If the total bill for a repair job was $160\$160, how many hours of repair work were performed?

  1. A
    33
  2. B
    44
  3. 55Answer
  4. D
    66
  5. E
    77

Answer

5 hours
Let hh represent the number of hours of repair work. The total charge is given by the sum of the fixed fee ($35\$35) and the hourly rate times hours worked (25h25h). Setting up the linear equation 35+25h=16035 + 25h = 160 and isolating hh gives 25h=12525h = 125, which simplifies to h=5h = 5. Thus, 5 hours of work were performed.

Step-by-Step Solution

1
Define the variable and set up the linear equation
35+25h=16035 + 25h = 160, where hh is the number of repair hours.
The total cost is the sum of the fixed diagnostic fee and the hourly charge multiplied by hours worked.
2
Subtract the fixed fee from both sides of the equation
25h=16035    25h=12525h = 160 - 35 \implies 25h = 125
Isolate the variable term containing hh.
3
Divide both sides by the hourly rate coefficient
h=12525=5h = \frac{125}{25} = 5
Solve for hh.

Key Concept

Formulating and solving linear equations in one variable from real-world scenarios
Rate this question