Question

An advertiser goes to a printer and is charged $42 for 50 copies of one flyer and $61 for 150 copies of another flyer. The printer charges a fixed setup cost plus a charge for every copy of single-page flyers. Find a function that describes the cost of a printing job, if is the number of copies made. C(x) =

Answer 1

c(x) = .19x + 32.50

Explanation:

The cost depends on the number of copies. The x value is the number of copies and the y value is the cost

c(x) = mx + b We need to find the rate of change.

(50,42) (150.61) The rate of change is the change in y over the change in x.

The y values are 61 and 42. The x values are 150 and 50

`(61-42)/(150-50)` =
`(19)/(100)` = .19

We also need the y intercept. We will use the slope of .19 and the x and y values of one of the points. We could use either point, I am going to use the point (50,42)

y = 42

x = 50

m =.19

y=mx + b

42 = .19(50) + b

42 = 9.5 + b Subtract 9.5 from both sides

32.50 = b

y = mx + b

y = .19x + 32.50 or

c(x) = .19x + 32.50