Chapter 6.1, Problem 39PPS

a.

To determine

To write: The conclusion based on the given information.

Explanation of Solution

Given:

Website A had 512 million visitors in year 2012 whereas website B had 131 million visitors in the same year.

In year 2016, website had 476 million visitors, and website B had 251 million visitors.

Calculation:

The number of visitors of website A is decreasing at the rate 9 million per year and the number of visitors of website B is increasing at rate 30 million per year.

b.

To determine

To describe: The solution process in making the conclusion.

Explanation of Solution

Given:

Website A had 512 million visitors in year 2012 whereas website B had 131 million visitors in the same year.

In year 2016, website had 476 million visitors, and website B had 251 million visitors.

Calculation:

Let x represents the number of years since 2012 and y represents the number of visitors in million.

The points corresponding the website A are $\left(0,512\right)$ and $\left(4,476\right)$ .

Similarly, the points corresponding to website B are $\left(0,131\right)$ and $\left(4,251\right)$ .

The slope of the line for website A is $m=\frac{476-512}{4-0}=\frac{-36}{4}=-9$ .

The slope of the line for website B is $m=\frac{251-131}{4-0}=\frac{120}{4}=30$ .

So, the number of visitors of website A is decreasing at the rate 9 million per year and the number of visitors of website B is increasing at rate 30 million per year.

c.

To determine

To write: The assumption made in making the conclusion.

Explanation of Solution

Given:

Website A had 512 million visitors in year 2012 whereas website B had 131 million visitors in the same year.

In year 2016, website had 476 million visitors, and website B had 251 million visitors.

Calculation:

The assumption made in making the conclusion was that the number of visitors both the website are increasing or decreasing linearly.