Should be in Consolidated List: BBPg. 796 #19

Test Preparation SAT Preparation
1

<li>The cost of maintenance on an automobile increases each year by 10 persons and Andrew paid $300 this year for maintenance on his automobile. If the cost c for maintenance on Andrew’s automobile n years from now is given by the function: c(n) = 300x^n, what is the value of x?</li>
</ol>

<p>A .1
B .3
C 1.1
D 1.3
E 30</p>

<p>The answer is 1.1, which I got with educated guessing.</p>

<p>I think I knew how to set it up but could not get anywhere. I tried to make it into a geometric sequence, with a subn = a sub1 * r^(n-1). I plugged 300 in for both a subn and a sub1 and simplified to get 1 = .1^(n-1). I got stuck here, but knew it couldn’t be .1 since it would get smaller, so I made it 1.1.</p>

<p>Can someone tell me what I’m missing?</p>

<p>Ah, I have so many topics! Oh well, just trying to do well. I’d ask my teachers, but there’s literally no time for me after school.</p>

2

<p>The question says an increase of 10% to the original for each year. Therefore, $330 would be a 10% inc. in 1yr.
Then plug it in for the cost function
330 = 300 x ^ 1
x= 1.1</p>

3

<p>Crap, I made it harder than it was supposed to be.</p>

<p>If I hadn't learned about geometric sequences within the past weeks, I probably would've gotten it :P</p>