Question

The scatter plot shows the number of DVDs Aaron sold in different months:

What is the approximate predicted number of DVDs Aaron will sell in the 13th month?

380
390
400
420

Answer 1

The answer is 380

Explanation:

Answer 2

We'll say that months = n.

Make a set of the DVD's sold:


`{20, 50, 80, 110, 140...}`

In month 1, Aaron sold 20 DVDs. There is no data for month 0.

There is a constant increase of 30 DVDs every month. We can make an equation out of this to fit this data set:


`a = 30n - 10`

a represents the DVDs made.

We need to subtract 10 in this equation, as the starting point is 20, and the increase of 30 is different from the increase from n = 0 to n = 1.

We are looking for the amount of DVDs Aaron sold on the 13th month. Plug 13 into the equation:


`n = 13`

`30(13) - 10 = 390 - 10 = 380`

The predicted number of DVDs Aaron will sell on the 13th month is 380.