Question

1. a moving company charges $800 plus $16 per hour. another moving company charges $720 plus $21 per hour. how long is a job that costs the same no matter which company is used?

Explanation:

Step1: Set up cost - equations

Let $x$ be the number of hours of the job. The cost $C_1$ of the first moving company is $C_1 = 800+16x$. The cost $C_2$ of the second moving company is $C_2=720 + 21x$.

Step2: Set the two equations equal

We want to find when $C_1 = C_2$, so we set up the equation $800+16x=720 + 21x$.

Step3: Solve for $x$

First, subtract $16x$ from both sides: $800=720 + 21x-16x$. Simplify to get $800=720 + 5x$. Then subtract 720 from both sides: $800 - 720=5x$, which gives $80 = 5x$. Divide both sides by 5: $x=\frac{80}{5}=16$.

Answer:

16 hours