00:01
So in this problem, we're told that the population density of the united states has been steadily increasing since the year 2000.
00:07
And this model, p equals 0 .82t plus 78 .5 represents the population density, where p is the population density, measured in people per square mile, where t is the number of years since 2000, meaning if i substitute 0 in place of t, that represents the year 2000.
00:24
So in part a, they want us to determine the population density in the year 2018.
00:29
Now, we're not going to substitute 2018 in for t, because remember, t is the year since 2000.
00:35
So to figure out our t value, we're going to figure out how many years since 2000 is 2018.
00:40
To do this, we'll subtract 2018 by 2000, which is equal to 18.
00:45
So in this case, we're going to substitute 18 in place of t.
00:49
So p will equal to 0 .82 times 18 plus 78 .5.
00:56
So now we can put this in our calculator.
00:57
So if i do 0 .82 times 18 plus 78 .5, that will give us our population density.
01:05
So the population density would be 93 .26.
01:09
Now, keep in mind, it's measured in people per square mile...