The price of a certain product changes with time, beginning with its release in 1982. In 1990, the product costs $49. Later, in 2020, the product costs $40.

If a linear model is used to describe the way the price (
) changes depending on the number of years since 1982 (
), what is the slope of this model? (Answer choices below are rounded to two decimal places.)
3.33
-0.30
0.30
-3.33
Undefined

1 answer

To find the slope of the linear model, we first need to calculate the change in price over the change in time.

Change in price = $40 - $49 = -$9
Change in time = 2020 - 1990 = 30 years

Slope = Change in price / Change in time
Slope = -9 / 30
Slope = -0.30

Therefore, the slope of the linear model representing the change in price of the product over time is -0.30. So the answer is B. -0.30.