An electrician charges a one-time fee of $75 plus $25 for each hour of service. If h is the number of hours and t is the total amount billed to the customer, th

Question

An electrician charges a one-time fee of $75 plus $25 for each hour of service. If h is the number of hours and t is the total amount billed to the customer, then the variables are related by the equation t =25h + 75. Which variable is the independent variable?

A. t

B. h

C. There is no relationship between the variables.

Answer 1

First, think about which would be the DEPENDENT variable. The total T is going to DEPEND on how many hours H the guys works.

 

Next, think about this: he can decide how many hours to work, right? That decision DOESN'T "depend" on anything else in the equation. So that number of hours H is the INDEPENDENT variable.

 

(As for choice C, OF COURSE there is a relationship between the two--the more the guy works, the more he charges!)

 

:-)