<p>So I'm preping for SAT, but I really can't figure out this math question. I don't understand how any of the answers the book gives you could be right.</p>
<p>Here it is:
If y is directly proportional to the square of x, and x=3 when y=18, then when y=2, x=</p>
<p>(a) 1/3
(b) 1
(c) 3
(d) 9
(e) 81</p>
<p>Could anyone help me out? ^_^;</p>
<p>y = k(x^2), where k is a constant</p>
<p>18 = k(3^2)
18 = k(9)
k = 2</p>
<p>y = 2(x^2)</p>
<p>2 = 2(x^2)
1 = x^2
x = 1</p>
<p>Is the answer in the book (B)?</p>
<p>Whoa, I understand it now. Thank you so much. When they said "square", for some reason I just kept thinking of the shape. n_n; </p>
<p>And yes, the answer was (b).</p>
<p>mishiru was this problem in the PR cracking the PSAT? i remember that Q :p</p>
<p>i got a 72 on the math somehow; i wonder if their math sections are easier than the actual thing..</p>
<p>Yeah, I'm reviewing. I'm in really bad shape if I can't even do some of the PSAT stuff, eh? ^_^; </p>
<p>72 in PR, the real PSAT, or real SAT? And yeah, I think PR is much easier then the real thing.</p>
<p>i got the 72 in PR</p>
<p>Oh, okay. Did you take the real PSAT yet, and was the score you got on that too far off? I want to know if I'm not preparing hard enough.</p>
<p>i got a 59 on the math. the only reason i wouldnt count that as accurate was because i didnt know that we could omit, so i guessed on the multiple choice i didnt know. that really hurt my score, so i feel maybe if i knew that i would have gotten mid 60ish perhaps? i think i guessed on 3-4 multiple choice so yea.</p>
<p>that 72 was a confidence booster for me though.</p>