Question

An electrician charges a $50 fee to make a service call plus $25 per hour he works. write an equation to represent the relationship between the two variables and tell whether or not it is proportional. explain your reasoning.

Answer 1

If x is the number of calls he makes and y is the number of hours he works;
the total amount he charges is termed as C
C = (50 * x) + (25 * y )
C = 50x + 25y
25y = C - 50x
the 2 variables are not proportional.
For 2 variables to be proportional, they need to be in the form y = mx 
Where m is a constant. When x increases, y too should increase by the same amount. 
The question given x and y are not proportional. As the number of hours he works and number of calls he charges are not dependent on each other. Therefore the 2 variables are not proportional.