Can you answer these SAT Math questions?

Test Preparation SAT Preparation
1

<p>1) <a href="http://i1053.photobucket.com/albums/s480/desuetudes/last.png%5B/url%5D"&gt;http://i1053.photobucket.com/albums/s480/desuetudes/last.png&lt;/a>
2 and 3) <a href="http://i1053.photobucket.com/albums/s480/desuetudes/47and48.png%5B/url%5D"&gt;http://i1053.photobucket.com/albums/s480/desuetudes/47and48.png&lt;/a>
4 and 5) <a href="http://i1053.photobucket.com/albums/s480/desuetudes/45and46.png%5B/url%5D"&gt;http://i1053.photobucket.com/albums/s480/desuetudes/45and46.png&lt;/a&gt;&lt;/p>

<p>They're really difficult. What answers did you get for these problems?</p>

2

<p>For 1, was the answer B. Two?</p>

<p>I think you have to use the system of three equations and solve for one of the variables, which you chose for test 2. </p>

<p>Points for Test 1: x
Points for Test 2: y
Points for Test 3: z</p>

<p>Since points x number correct = score,</p>

<p>34x + 15y + 9z = 177
33x + 19y + 7z = 172
35x + 17y + 10z = 189</p>

<p>& solve for y.
If you’ve got a TI-89, you can just plug in these three equations and solve for y.
y = 2</p>

<p>For #3, answer’s C. 3. </p>

<p>It helps if you set up the mean expression. </p>

<p>(1+3+2+x+1) / 5
Now you know that the mean has to be equal to one of the values so just set it equal to variable v (for value). </p>

<p>((1+3+2+x+1) / 5) = v</p>

<p>1+3+2+x+1 = 5v</p>

<p>7+x = 5v </p>

<p>Seeing this, you can plug in the given values for v to see which one works, and it’s fairly obvious that v=2 is the answer, so x=3.</p>

3

<ol>
<li>The only real x such that y = sqrt(-x^2) is a real number is x = 0. Hence the answer is B.</li>
</ol>

<p>4.
I is equal to (sin 2x)(1/(sin 2x)). Since x is not zero, sin 2x is not zero, so we can cancel sin 2x, leaving 1.
II is equal to sin 2x. Clearly this does not equal 1 for all values of x.
III is just the Pythagorean identity, this equals 1.
Therefore the answer is D.</p>

<ol>
<li>The population is multiplied by 1.1 each day. After 100 days, the population is (1.1)^100 ≈ 13781 times today’s population, E.</li>
</ol>