Question

A yearbook printer charges based on the number of pages printed. Here is a table that shows the cost of some recent yearbooks.

Number of pages 50 100 150 200
Cost 1.25 1.85 2.45 3.05


Which equation gives the cost, y, in terms of the number of pages, x?


y = 0.012x + 0.65


y = 0.012x + 1.25


y = 0.012x + 49.985


y = 83.3x + 0.65

Answer 1

y = 0.012x + 0.65

Explanation:

In order to confirm which equation gives the cost of y in terms of the number of pages x, each and every equation needs to be checked out.

Assuming y = 1.25 and x = 50 (as given in question)

First Equation:

y = 0.012x + 0.65

y = 0.012(50) + 0.65

y = 0.6 + 0.65

y = 1.25

Second Equation:

y = 0.012x + 1.25

y = 0.012(50) + 1.25

y = 0.6 + 1.25

y = 1.85

Third Equation:

y = 0.012x + 49.985

y = 0.012(50) + 49.985

y = 0.6 + 49.985

y = 55.985

Fourth Equation:

y = 83.3x + 0.65

y = 83.3(50) + 0.65

y = 4165 + 0.65

y = 4165.65

Hence, only the first equation is resulting in the cost y in terms of the number of pages x. Therefore, is the correct one.

Answer 2

Using the first X and Y value replace the values in the equation and see which one works:

1.25 = 0.012(50) + 0.65

0.012(5) = 0.6 +0.65 = 1.25

The first equation works

Now try the second set: of values to check:

1.85 = 0.012(100) +0.65

0.012*100 = 1.20 + 0.65 = 1.85

The first equation is the correct one.