May SAT 2011: Math Section

Test Preparation SAT Preparation
441

<p>To elucidate Xiggi’s statement and to put to rest the debate over the Volume-Area question:</p>

<p>If X and Y are directly proportional, (X/Y) = (2X/2Y) = (nX)/(nY)</p>

<p>For example:</p>

<p>X^2 and Y^2 are directly proportional because when X = 2 and Y = 3, you get
4/9
and when you double both, such that X = 4 and Y = 6, you get…</p>

<p>16/36, which simplifies to 4/9</p>

<p>X and Y^2 are not directly proportional; (X/Y) does not necessarily equal (2X/2Y) or (nX/nY)</p>

<p>For example: given that X = 2 and Y = 3, you get (2/3)</p>

<p>But when X = 4 and Y = 6, you get (4/36), or (1/9). 2/3 does not equal 1/9. </p>

<p>Two variables–here, area and volume, are directly proportional when they are set equal to one another with equal powers. Other factors, such as constants (here, 6 multiplied by the area) do not matter.</p>

442

<p>1) x was 5 more than 10. What is x? Answer: 5
2) 7k=k^2
3) 23 weeks
4) Diameter was 12
5) Numbers 3<em>5</em>11 (165)
6) Proportion of net income: 1 to 6
7) Point B < WHAT WAS THE QUESTION???
8) India
9) 1/ (n+1) (20th question in 20Q section)
10) 14 was the y coordinate of point P on a circle
11) The area was 18 (question #3)
12) stars: 24
13) 250
14) 0.3 % (17-b)
15) Which function cannot be f(something)=-5
16) the probability over 500: 18
17) total registered voters: 3500
18) the probability of choosing x and y from 1 to 10 numbers and placing in II quadrant is zero (none)
19) 9/5 is 9/5
20) 3.84 for the last gird-in
21) I, II, III for the last MC before gird-in
22) Two and One for choosing a 14 consequent numbers
23) if f(n)=n^2-n what is the value of f(-1)? 1+1=2
24) the degree measure of similar triangles x+y+z=240
25) 8.5 miles
26) y/x
27) number 7 in 18Q section: small triangle in big triangle (answer was C)
28) the right triangle is divided into three nonoverlapping angles: 2x; 3x; and 5x; What is x? 9
29) pen question: 4000
30) length of an arc: pi
31) 4<em>square root of 2
32) triangle x was 10 degrees
33) 8.105
34) A^3/2
35) 23 days
36) parallel lines: 72
37) reflection above line x (downward parabola; the same as –x^2)
38) 10-D 2</em>L*W/ L^2+W^2=3/4
39) mx+b. The product of mb is
40) 4.5
41) the shoe size was 7.5 i think?
41) 1.333 <= I STILL DONT KNOW WHAT THE QUESTION WAS</p>

443

<p>why is number 9 1/n+1 instead of -1/n^2?</p>

444

<p>Sauternety- the 1.333 one was a number line</p>

445

<p>no, it doesnt matter that there are 6 sides, it said they had to be directly proportional, not equal</p>

<p>& yup. i remember 1.333</p>

446

<p>can anybody PLZ tell me the question in which the answer was 9/5???
i don’t ever remember putting a 9/5</p>

447

<p>

</p>

<p>What did you plug in to make it … work? </p>

<p>Do yourself a favor and use some numbers. If you have a cube with v=8, the total surface is 24. Is 24^2/3 equal to 8? I don’t think so!</p>

<p>Oh well, you should relax until you get your scores. Nothing you can do about it now. :)</p>

448

<p>that A^(3/2) one was so weird</p>

<p>I kept plugging in dimensions for a cube’s V and SA… NONE of the answers worked for me!! I omitted it i think :(</p>

449

<p>JBCHUN and westfbulldogs, are you guys sure it was ^2/3?</p>

<p>I got that too, but I didn’t have time to check it. I took the 3rd root of V^2 which, when simplified, gives ^2/3</p>

<p>Is that what you did?</p>

450

<p>Can somebody please explain this “number line” problem to me? I don’t remember getting the problem or the answer 1.33 at all.</p>

<p>If you’d prefer to send me a PM, that’d be really nice too. Thanks!</p>

451

<p>you seem to all make the common mistake:
It’s not when does V=A, it’s a matter of V being DIRECTLY PROPORTIONAL to A.
Proportions are a lot different from equivalence…
It’s all in the matter of if the ratios stay the same as they increase.
Therefore, V is directly proportional to A^(3/2)</p>

<p>Think of it like this:
V is CUBED (meaning x^3)
A is SQUARED (meaning x^2)</p>

<p>So, to make them increase at the same rate (i.e. directly proportional), you would want to make x^2 become x^3.
Gee how would we do that?
Maybe raising x^2 to the (3/2) power
E) A^(3/2)</p>

452

<p>it was a lot closer than using a^3/2
no need to be obnoxious about it lol.</p>

453

<p>dvdhsu- the question was something along the lines of this…</p>

<p>1.2–Q–|–|–|–|–1.8</p>

<p>Q represents the number on the numberline tha they asked for, since each increment increases by .1, it would be closest to about 1.3</p>

454

<p>i think the answer wasnt exactly 1.33 more like 4/3.</p>

455

<p>that’s a pretty big margin of error sauternety, that would mean it was like 3 notches over. I believe that question was multiple choice, I’m not gonna say you’re wrong just cause I don’t have a test in front of me with an answer key, but I really think it’s 1.333</p>

456

<p>actually im pretty sure it was in fractions - some of the choices were 6/5, 5/4, 4/3, 3/2… jogged your memory?</p>

457

<p>the number line question was definitely 1.33, i almost messed up because i didn’t read it at first so i had to double check everything.</p>

<p>edit: oh, are you debating whether it was in fractions or not? it was!</p>

458

<p>HAHA we’re both stupid!! sorry for some reason I read your 4/3 as 3/2</p>

<p>4/3 is EQUAL to 1.333, we’re both right though…</p>

459

<p>guys what was the question to number 2</p>

460

<p>Thank you so much jd989898, I remember it now.</p>

<p>Appreciate it!</p>