Chapter 8.3, Problem 25STP

To determine

The number of hour’s n that the electrician worked

Answer to Problem 25STP

The equation is $35+80n=915$

Option D is correct

Explanation of Solution

Given:

An electrician charges $35 for a house call and $80 per hour for each hour worked and the total charge was $915

Concept Used:

Rules of Addition/ Subtraction:

• Two numbers with similar sign always get added and the resulting number will carry the similar sign.
• Two numbers with opposite signs always get subtracted and the resulting number will carry the sign of larger number.

Rules of Multiplication/ Division:

• The product/quotient of two similar sign numbers is always positive.
• The product/quotient of two numbers with opposite signs is always negative.

In order to find an equation the number of hours n that the electrician worked , first multiply its rate of $80 per hours to n and then add the house call fee of 35 as shown below,

  $\begin{array}{l}80\times n\\ 80n+35=915\\ 35+80n=915\end{array}$

Thus, the equation is $35+80n=915$

Option D is correct