Question

The cost to download music from an Internet site is shown.

According to the information in the table, which equation describes the relationship between the number of songs downloaded and the cost to download?

A. c = 1.5n
B. c = 1.5n + 25
C. c = 7.75n
D. c = 7.75n + 25

Answer 1

Option (B)

Explanation:

If we graph the points given in the table, a straight line is obtained which shows that the table given represents a linear function.

Let the two points on the graph are (4, 31) and (8, 37)

Slope of the line passing through these points,

m =
`(y_2-y_1)/(x_2-x_1)`

=
`(37-31)/(8-4)`

= 1.5

Equation of the line passing through a point (4, 31) and slope = 1.5 will be,

y - y' = m(x - x')

y - 31 = 1.5(x - 4)

y = 1.5x - 6 + 31

y = 1.5x + 25

Therefore, Option (B) will be the answer.