Math Question help please! (&Quick Question on PR 11 test book)

<p>I'm taking the PR 11 tests (yes I know, the blue is better) BUT this one has answers in it, with explanations. So, my relatively quick question is: How similar are these to the actual SAT? In terms of math/CR/and writing separately. What areas is it strong/weak in mimicking?</p>

<p>Now, onto the question. I strongly believe the book made an error, but I could just be stupid.</p>

<p>17.
The cost for coal from a certain company is $15 for the first pound plus $6 for each additional pound of coal. Which of the following functions gives the total pound of coal C(p), in dollars, for p pounds of coal?</p>

<p>(A) C(p)=6p-15
(B) C(p)=6p-9
(C) C(p)=6p
(D) C(p)=6p+9
(E) C(p)=6p+15</p>

<p>Answer Below:</p>

<p>The book says the answer is B.</p>

<p>The answer is D. I think the book made a mistake. Try plugging in numbers and you should see that it's impossible for it to be B.
If there are 3 pounds of coal the total cost is 15 + 12 = 27. The only solution that works is D. </p>

<p>Also, setting up the equation yields, c(p) = 15 + 6(p-1) = 15 + 6p -6 = 9 + 6p</p>

<p>yea its D. when its 1 pound, its D, lmao,its a negative answer in B. loL...
if u have alot of time,say,u're a sophomore or junior, then u can mess around using PR and other crap, then get into the BB; however,i really dont see the need to use pr lol..</p>

<p>Princeton Review has alot of errors.
They range from incomplete questions, to no correct answer choices, to wrong explanations.</p>

<p>In test #1 alone, I encountered no less than 4 errors.</p>

<p>The answer is D. PR fails.</p>

<p>15+ 6(P-1)
15+6P-6
6P+9
D.</p>

<p>hey, i feel really stupid right now but i don't understand how you guys are setting up the equation. Can someone explain why it's 6(P-1)? Where does the p-1 come from? </p>

<p>Sorry if this is a dumb question but you guys confused me. I though it would be 15 + 6P?</p>

<p>P-1 because the first pound doesn't count. We already added 15 for the first pound, thus each pound after that is 6. Therefore we have to take that into account and subtract 1 from the total pounds.</p>

<p>its P-1 because you already have accounted for the first pound with $15.</p>

<p>ohh i get it. i never thought of that lol i knew it had to be some dumb explanation. thanks =]</p>