Explanation for Question 22 From the Math (Calc) Section on the Official Sat Practice Test 10
Now question number 22 says that first year Eleanor, 2 the first year Eleanor organized a fundraising event, 3 she invited 30 people. So in year one, 4 she's inviting 30 people. And then for each of the next five years, 5 she invited double the number of people, 6 right? So we started at 30 in year one, 7 and then as we go down here, she's going to double each 8 time. It says if F of N is the number of people invited 9 to the fundraiser and years after Eleanor began the event, 10 which of the following statements best describes the function F right. 11 So first thing we can ask ourselves is what do we already know about 12 F and when we ask ourselves about a function, 13 a good first question is, is it linear or exponential? 14 And we see here that we're multiplying by a constant number. 15 And if I do that, this is what I get, 16 right? 17 We see up here, we multiplied by two, but we could also call that 18 going up 30, maybe here we multiplied by two, 19 but we could call that going up by 60 here, we could call it 20 going up by 100. Let me ask ourselves, 21 are we increasing by a constant amount? 22 Right? No, the number we increase changes every time. 23 So it's not linear. We're multiplying, 24 which tells us that this is an exponential function, 25 right? And it's obvious, quite obvious here that our numbers are increasing, 26 right? As things go along with this function is increasing. 27 The numbers get larger and larger so we can eliminate a immediately cause a 28 is,...