Answer Choices
P= 862 − 1.6t
P= 862 − 16t
P= 862 + 16 (t− 2,000)
P(t) = 862 - 1.6(t - 2,000)
Explanation for Question 25 From the Math (Calc) Section on the Official Sat Practice Test 8
So question 25 gives us a table with some population information for Greenleaf, 2 Idaho, and they want us to create a function that shows the population 3 of green leaf tea years after 2000. 4 So one important thing we can notice is what our starting point is. 5 Our starting point is our population in 2000, 6 which is 862. We can see that all of our answer choices say this, 7 but some have a negative sign, a subtraction sign, 8 right? And some are adding. And so one important thing to note is that 9 our population has in fact decreased from 2000 to 2010. 10 So that one answer choice that would say we're increasing the population would be 11 wrong. Cause we need that negative sign to show that our population is decreasing. 12 And now the question is by how much, right? 13 So we see that it has decreased by 16, 14 here from 2000 to 2010. 15 And so you might be tempted to pick answer choice B because you see 16 a 16 what's important to notice is that the 16 was over the course 17 of 10 years. Right? And we need to know for time T the 18 decrease in one year. So if we decrease 16 over the course of 10 19 years, and we divide those, we see that each year we actually decreased by 20 1.6 people. So our best answers going to be a cause that shows the 21 decreased by 1.6 people. And one thing about 22 D that makes D wrong cause he does have the 1.6 is that it 23 says T years after 2000. 24 So by saying years after 2000, 25 we don't need to subtract another 2000. 26 For example, in 2003 T would be equal to three. 27 But if we do this and we do tea or not, 28 tea three minus 2000, 29 your years ended up going negative. And that doesn't make any sense because we 30 can't have a negative year. So we don't need to subtract 2000. 31 We can just keep it as tea. And our best answer is going to 32 be a.