Tough Math Question

Test Preparation SAT Preparation
1

<p>Would appreciate it if someone could explain this to me:</p>

<p><a href="http://i46.tinypic.com/2r3e8uw.png%5B/url%5D"&gt;http://i46.tinypic.com/2r3e8uw.png&lt;/a&gt;&lt;/p>

<p>Thanks in advance.</p>

2

<p>Connect the centres of the 4 circles and you get a 2by2 square. Thus finding the diagonal of the square is 2root2.
2root2 is the radius of 2 circles and the diameter of the smaller circle. so the diamater of the smaller circle is 2root2-2
the radius of the smaller circle is (2root2-2)/2
answer is C</p>

<p>draw it out :D</p>

3

<p>Connect the centers of any three larger circles, you have a right triangle.
Let the radius of the smaller circle be r, then you have the following equation</p>

<p>2^2+2^2=(2+2r)^2 (Pythogrean theorem)
8=(2+2r)^2
2 sqrt(2)=2+2r
r=sqrt(2)-1
so the answer is D.</p>

<p>Nath your simplified version is D, not C</p>

<p>Edited to explain where the first equation come from.</p>

4

<p>E is not correct.</p>

5

<p>Wow, that was simpler than I expected. Thanks guys.</p>

6

<p>@wildwood</p>

<p>I got most of your explanation, except why you subtract 1 at the end.</p>

<p>Damn, I refuse to leave this thread until I understand!</p>

<p>EDIT: I am incredibly slow… I got it now :)</p>

7

<p>Here’s another one: <a href=“http://i45.■■■■■■■.com/9kbbl2.png[/url]”>http://i45.■■■■■■■.com/9kbbl2.png&lt;/a&gt;&lt;/p&gt;

8

<p>Can anyone explain to me the SAT QofD: [The</a> Official SAT Question of the Day](<a href=“The SAT – SAT Suite | College Board”>The SAT – SAT Suite | College Board)</p>

<p>What is the best way/method/formula to go when this kind of question shows up?</p>

9

<p>Just plug in numbers.</p>

10

<p>@PurpleKoala
where are these questions from?</p>

11

<p>I tried, but I don’t know how to get the answer for some reason. Can you show me an example? I assumed that d is 10.</p>

12

<p>They’re from this SAT PDF I found online. Could someone please answer question 14? <a href=“http://i50.■■■■■■■.com/ctch2.png[/url]”>http://i50.■■■■■■■.com/ctch2.png&lt;/a&gt;&lt;/p&gt;

13

<p>@purple: in this question, the correct answer is: C (the 2 represents the quantity c)
for every new pail you add to the stack, the total height will increase by the extra height added by the new pail to the stack. this extra height is the quantity which does not get inside the stack, thus c</p>

14

<p>But I don’t understand what the 8 is equal to?</p>

15

<p>I think the answer is C because you have 2 pails of stack, thus the height altogether is 12.</p>

16

<p>@seachai:
you simply write the english language in equation form. let us write a for apples and p for a pound
they tell you 10 pounds of apples cost d dollars, thus 10p=d
also 6 apples weigh 1 pound, thus 6a=p
by substituting the second equation in the first one, we get: 60a=d or 60 apples cost d dollars. Since we want the price of a dozen apples, we divide 60a by 12 to find the number of dozens: 60a/12=5 dozens cost d dollars therefore One dozen costs d/5 dollars which is d*100/5 cents= 20d cents. The correct answer is A</p>

17

<p>@purple: the 8 is equal to (a-b) : it is the height of the first pail which is not “covered” by the following pail</p>

18

<p>Why can’t 8 equal ‘c’ and the 2 equal the uncovered part?</p>

19

<p>No, each side measures a 4. There are four radius’ length, each one is 1 unit.</p>

<p>The hypotenuse is 4<em>sqr(2). The radius is 4</em>sqr(2) - 4 divided by 2. Remember, we’re looking for its radius, not diameter. This simplifies to 2sqr(2)-2 , which isn’t in the answer choices, so the question is wrong.</p>

20

<p>For the second one, I agree with everyone that it’s C…</p>