Need help with a few math problems...

Test Preparation SAT Preparation
1

<p>Can someone please explain these:</p>

<p>First set: <a href="http://i32.tinypic.com/2wefbbt.jpg%5B/url%5D"&gt;http://i32.tinypic.com/2wefbbt.jpg&lt;/a&gt;&lt;/p>

<p>Second set: <a href="http://i25.tinypic.com/344a3qe.jpg%5B/url%5D"&gt;http://i25.tinypic.com/344a3qe.jpg&lt;/a&gt;&lt;/p>

<p>Third set: <a href="http://i28.tinypic.com/2h38s3r.png%5B/url%5D"&gt;http://i28.tinypic.com/2h38s3r.png&lt;/a&gt;&lt;/p>

<p>Thanks.</p>

2

<p>First set:
19. The answer is C. Each unit on the vertical axis represents 1 ft. If the depth decreased 10% between 3 PM and 4 PM which on the graph is 2 units, then at 3 PM, the depth must have been 20 ft (2x10). It follows that at 4 PM, the depth was 20-2 or 18 ft.</p>

<ol>
<li><p>The answer is A. Subtract k from both sides in the equation they gave you and you get h=7-k. Substitute 7-k for the denominator of the expression and you get (7-k)/(7-k) which equals 1.</p></li>
<li><p>The answer is E. Solve x squared= x+6 for x and you get x= -2 or 3. The only answer that works for both of those solutions is E (x squared>x).</p></li>
</ol>

<p>I’ll try and get more done later. Tell me if you don’t understand any of those.</p>

3

<p>Oh, I need some of those answered too! I just finished College Board’s prep test online. :)</p>

4

<p>Thanks, any help is appreciated.</p>

5

<p>Set 1 [Imageshack</a> - satqs.png](<a href=“http://img411.imageshack.us/f/satqs.png/]Imageshack”>ImageShack - Best place for all of your image hosting and image sharing needs)
Set 2 [Imageshack</a> - sat2.png](<a href=“http://img204.imageshack.us/i/sat2.png/]Imageshack”>ImageShack - Best place for all of your image hosting and image sharing needs)
Set 3 [Imageshack</a> - sat4.png](<a href=“http://img188.imageshack.us/i/sat4.png/]Imageshack”>ImageShack - Best place for all of your image hosting and image sharing needs); 15. is 6.5, not 5.5 (error)</p>

<p>Just click on the image to zoom in, not the magnifying glass</p>

6

<p>Third set:
13. The answer is B. You already have angles k and p so you need an angle equal to n. Vertical angles are equal so s and t are equal. Alternate interior angles are equal so t and n are equal. By transitive property, s and n are equal.</p>

<ol>
<li><p>The answer is 6.5. This one is hard to explain without the diagram. Divide the figure so you get 1 rectangle with an area of 2 and a smaller rectangle under it. That smaller rectangle has an area of 1/4 (9/4-2) so the width of the smaller rectangle must be 1/4 as well. Add up all the sides and you get 6.5 (1+2+1+1/4+1+1/4+1).</p></li>
<li><p>The answer is 5/9. You can just list out all the possibilities and circle the ones that are divisible by 5.</p></li>
</ol>

7

<p>@TRUFFLIEPUFF: The answer for for Set 1 Problem 19 is C (18 ft). The problem is asking for the depth at 4 PM not 3 PM.</p>

8

<p>^ Yes, that’s what my answer is for: the depth at 4 PM, which is 20 ft.</p>

<p>It can’t be 18 ft at 4 PM. Since 3 PM to 4 PM is 10% and there are two lines, that means each line represents 5%. 18 x .05 = 0.9 ft for one line. However, the problem states that each line is 1ft.</p>

9

<p>^The depth at 4 PM is 18 ft though. If the depth at 4 PM was 20 ft, then that would mean the depth was 22 ft at 3 PM. The problem said the depth decreased by 10% from 3 to 4 PM. 2 ft is not 10% of 22 ft.</p>

10

<p>Set 2, #6:</p>

<p>Note that the numbers are real numbers (that is, they don’t have to be integers or rational). </p>

<p>We know that 6 is the fourth number, so there are only two “slots” between 2 and 6. Since 3 appears the most times, 3 must appear exactly twice. From the given information, we know that the set is {2, 3, 3, 6, a, b, 20} (in order from least to greatest). We are given that 3 appears the most times. In order for this to be true, a cannot be equal to b (since if that were the case, both 3 and a would appear the same number of times).</p>

<p>Thus, the mean is (a+b+34)/7, where a and b are distinct real numbers. Guess and check:</p>

<p>I: a+b = 15. Possible. (example: (a, b) = (7, 8))
II: a+b = 25.5. Possible. (example: (a, b) = (10, 15.5))
III: a+b = 36. Possible (example: (a, b) = (17, 19))</p>

<p>The answer is E.</p>

11

<p>

You don’t multiply 18 by 0.05; you multiply 20 by 0.05, which equals 1 ft. Your way is a little inefficient though so it’s hard to explain off of that.</p>

12

<p>^^ But if it was 18 ft at 4 PM that would mean it would be 19.8 ft at 3PM (2 of 0.9 fts each line) which means the difference is 1.8. However, 1.8 is, too, not 10% of 19.8; 1.98 is.</p>

13

<p>^But the problem already states that each unit of the vertical axis represents 1 ft. So if it was 18 ft at 4 PM, that would mean it was 20 ft at 3 PM. A 10% decrease from 20 ft would be a decrease of 2 ft, the actual amount it decreased according to the graph. I can’t explain more than that…</p>

14

<p>Oh wait never mind I see why it is 18 at 4 PM. I stand corrected haha.
Wow, it would be easier to just add 2 ft as you did to each choice and test for 10% :o lulz</p>

15

<p>^I’m glad you got it because I don’t think I could have explained further. :)</p>

16

<p>^ Haha yeah, I think I overanalyzed the problem a bit too much</p>

17

<p>Thanks everyone. @TRUFFLIEPUF, 20 for set 1, according to the answers, is actually D, not E as you indicated. Can you please take a look at that one again? Thanks.</p>