Math Question

Test Preparation SAT Preparation
1

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2

<p>I think the Fastest way, for me anyways, would be to plug&chug. Lets say the truck has 5 axles. What would the toll be for a truck with 5 axles? (n=5)</p>

<p>Well the 1st 2 axles cost $2, the remaining three cost $6. The toll is $8.</p>

<p>Plug n=5 into each choice, and see which one(s) yield 8. </p>

<p>A. Works
B. Doesn’t
C. Doesn’t
D. Doesn’t
E. Doesn’t</p>

<p>Answer is [A]</p>

3

<p>(Extra Tip for the problem)</p>

<p>If n is a real number than choices are in following order of magnitude:</p>

<p>(E)>(D)>(C)>(B)>(A)</p>

<p>This helps eliminating answers quickly.</p>

4

<p>No need to plug it in, if you don’t want, though.
If n is the number of axes, than (T(n)=2(n-2)+2) = (2n-4+2)=(2n-2).</p>

5

<p>^I was about to say that method, but my method I think is simpler, and possibly faster (only takes ~20-30 seconds).</p>

6

<p>can you explain your extra tip, I get the answer now though :)</p>

7

<p>In my extra tip, all I’m saying is that for instance, Choice (B) is greater than choice (A).</p>

<p>When you plug in n=5, </p>

<p>(A)=8
(B)=9
(C)=10…</p>

<p>If you notice this pattern that the choices are increasing by 1, you can solve the problem just a little bit quicker.</p>

<p>(A) t(x)=2n-2
(B) t(x)=2n-1
(C) t(x)=2n
(D) t(x)=2n+1
(E) t(x)=2n+2</p>

<p>If you notice, each option is going up by 1, so if (A) works (A=$8), there is no way that any of the other options are going to work (no other options will be $8).</p>

<p>– </p>

<p>If you don’t understand what I’m saying, its not that big of deal. I’m just trying to increase your understanding of the problem, so you will be able to solve the same type of problem again, except a bit quicker.</p>

8

<p>I understand it thanks.</p>