Praxis Core Academic Skills for Educators: Mathematics (5733)Algebra and FunctionsMedium
A plumber charges a service fee of $75 plus $60 per hour for labor. If a customer's total bill was $255, how many hours did the plumber work?
- A3 hours
- B2 hours
- C3.5 hours
- D2.5 hours
Show answer & explanationAnswer & explanation
Correct answer: A. 3 hours
Let 'h' be the number of hours worked. The total cost can be represented by the equation 75 + 60h = 255. Subtracting 75 from both sides gives 60h = 180. Dividing by 60 gives h = 3 hours.
Why the other options are wrong
- B. This would result in a total bill of $75 + 60*2 = $195.
- C. This would result in a total bill of $75 + 60*3.5 = $285.
- D. This would result in a total bill of $75 + 60*2.5 = $225.
Solving Linear Equations
The process of finding the value(s) of the variable(s) that make a linear equation true.
- Involves isolating the variable using inverse operations.
- Operations must be applied equally to both sides of the equation.
- Common steps include combining like terms, distributing, adding/subtracting, and multiplying/dividing.
Memory trick: Translate to math, isolate the unknown, check your work!