November 2012 SAT Math Level II Discussion

<p>For the one with x,y,z it was y=3/2 right?</p>

<p>yes its 3/2</p>

<p>Wait. Period was 2Pi?</p>

<p>I thought the equation was abs(cos(1/2(x)))+3?</p>

<p>but Absolute value shifts the negative part of graph up, so period is divided by 2.</p>

<p>what q is xyz</p>

<p>It’s always good to draw up lists, so here goes for whatever’s been discussed so far, in no particular order:</p>

<ol>
<li><p>Product of 3 consecutive numbers is always divisible by 2 and 3, not necessarily 4. 1,2,3 and 9,10,11 are examples.</p></li>
<li><p>What does y approach as x approaches 3/2? It increases without bounds.</p></li>
<li><p>What is the locus of the points equidistant from (1,1,3) and (1,2,3)? Y=3/2.</p></li>
<li><p>What is the length of the segment in terms of theta? 1 - cos(theta).</p></li>
<li><p>If x = arctan(y), then what is sqrt(1 - y^2)? Abs(secx).</p></li>
<li><p>First pick 4 samples out of 10, then pick one among the four - what are the number of such selections? 10C44C1 = 7280.</p></li>
<li><p>Four weights in pounds are 1.1, 1.1, 1.3, 1.3 and the standard deviation is 0.1. If each is placed in a box of 2 pounds, what is the standard deviation of the new weights (including boxes)? The new weights are 3.1, 3.1, 3.3, 3.3, and the standard deviation does not change. It remains 0.1.</p></li>
<li><p>The probability of a call being non-local is 1/3, the probability of it being local is 2/3. What is the probability that out of two independent calls, one is non-local AND the other is local? For two independent events occurring sequentially, especially joined by the AND clause, their probabilities are to be multiplied. The answer, therefore, is 2/9, and not 4/9 (Feel free to correct me if I’m wrong, though). </p></li>
<li><p>(6 triangle 4) (+) (5 triangle 3) = 2.5. Triangle was division, (+) was multiplication. The answer to the following question using these symbols, if my memory serves me right, was 2.</p></li>
<li><p>x = x^2 + bx + c; what is the maximum number of real roots possible for this equation? It is a quadratic, hence the maximum possible real roots is 2.</p></li>
<li><p>A 0.03 inch paper doubles in width for each fold. If it was folded 12 times, what is it’s width in FEET? Nearly 10 feet was the answer.</p></li>
<li><p>Which of these functions is the same as its inverse? The answers were 1. Y=1/x and 3. Y=(1/x-1) + 1.</p></li>
<li><p>Compare the slopes of the two lines if they are parallel. Answer was k=m.</p></li>
<li><p>Difference between maximum and minimum values of the function? Answer was 8.4.</p></li>
<li><p>The co-ordinates of the vertices of a square are given. If they are all doubled, what is the ratio of the area of the new square to the original? 4:1.</p></li>
<li><p>What is the area of the triangle where the top vertex corresponds to the maxima of the given function? Pi/2.</p></li>
<li><p>Vector addition, given the magnitudes are 4 and 8 with angle 50 degrees between them. I don’t remember well, and I don’t have a calculator nearby, but as somebody mentioned, it might have been 11.</p></li>
<li><p>Given a frequency distribution table, what is the mean? You have to multiply each value with its frequency, add them up, and divide the sum by 24, which was the total of the frequencies. Answer was 21.67.</p></li>
<li><p>Anybody remember the probability question where they asked how many ways its possible to pick two numbers with replacement so that they add up to 7? Was the probability of picking such numbers not 3/(10C2) = 0.06? There are three possibilities: (1,6), (2,5), and (3,4), while there are 10C2 ways to pick the numbers. Or did I do it wrong? Does the order of the ordered pair matter? Should I have counted (2,5) and (5,2) separately?</p></li>
<li><p>For the compund interest question, the wording was really awkward. The 3500 dollars were invested at “5.2% annual interest compounded quarterly”. What’s that supposed to mean? Annual interest, yet compounded quarterly? My answer was probably wrong, but what was the right one?</p></li>
<li><p>The rate of decomposition of a chemical is given by R = k
(C^m). Given two instance values for R and C, what is m? 2 was the answer.</p></li>
<li><p>What is the period of y = abs(cos(0.5x)) + 3? The answer was 2Pi.</p></li>
</ol>

<p>That’s about it so far. This list covers nearly half the test, so I’m sure we won’t have to repeat the same questions. Feel free to correct me if you think I’m wrong anywhere … I already got like 3 wrong. :/</p>

<p>Ah. I see. xD.</p>

<p>are you sure the phone thing is 2/9??
i got that but everyone kept saying it was 4/9</p>

<p>for 20. compound one it was $4,286
theres an equation but i forgot so what i did was</p>

<p>3500 * .052 = x
3500 + x = y</p>

<p>then repeat 3 more times</p>

<p>For the annual interest, I think I got 4074 or something.</p>

<p>3500 * 1.054 *1.054 * 1.054 * 1.054</p>

<p>Edit:Byahnoob is right. That’s what I got.</p>

<p>@TheBlueMarble. For the 7 one, I assumed that is was permutations because I believe it said the numbers were replaced or something along the lines of that. Therefore, I got 6 for the numerator, I don’t remember the denominator, but got .06 as my final answer as well.</p>

<p>was .06 choice B? i think i put A or B</p>

<p>It should be around 3692
3500*(1+(.054/4))^4</p>

<p>@TheBlueMarble</p>

<h1>9 I got 3</h1>

<h1>19 I also got .06 (but I wasn’t sure about this one)</h1>

<h1>20 I think I got 3685.57 (Which is 3500(1+(0.052/4))^4</h1>

<p>p.s. If I left 4 blank and got 5 wrong, what are my scores looking like?</p>

<p>For the square area question, the area will quadriple.</p>

<p>Edit: Nevermind.</p>

<p>i don’t think III was an inverse function. Checked twice</p>

<p>@Iris0208 - i think his right just use the equation but i dont get why what i did came out wrong</p>

<p>Its a compound interest formula. Should always work</p>

<p>Nevermind. That was the annual rate. >.<
I saw the interest rate as a quarterly rate. My bad.</p>

<p>for the interest q. x=x0x(1+.06)^4</p>

<p>I got 4319 for the compound… Im not sure though</p>