Sat hard-ish math problem

Test Preparation SAT Preparation
1

<p>Hello, i had a little issue withthis problem
It would be very nice if someone could explain me how to find this answer</p>

<p><a href="http://fr.tinypic.com?ref=v2tf87" target="_blank"><img src="http://i42.tinypic.com/v2tf87.jpg" border="0" alt="Image and video hosting by TinyPic"></a></p>

<p>There s the link if it doesnt show
<a href="http://i42.tinypic.com/v2tf87.jpg%5B/url%5D"&gt;http://i42.tinypic.com/v2tf87.jpg&lt;/a&gt;&lt;/p>

<p>Thank you in advance</p>

2

<p>You could do it on your own, but here’s the solution anyways : </p>

<p>1- Merge the two roots into one. that would give you an equation both sides of which have a square root. The equation reads : sqrt(2<em>3</em>xy)=sqrt(48)</p>

<p>2- Square both sides. That would leave you with : 6xy=48</p>

<p>3-Divide by 6 in both sides, which would give : xy=8</p>

<p>4- All the possible pairs that make an 8 are those : (1,8) (8,1) (2,4) (4,2)</p>

<p>5- You’re done, those are four. </p>

<p>You’re welcome.</p>

3

<p>Question is terribly worded, but the answer is A, 4. We have sqrt(6xy) = sqrt(48), so xy = 8. There are four pairs of positive integers that satisfy xy = 8.</p>

4

<p>Thank you so much for your clear and fast answer</p>

<p>However i got hardship with this one as well</p>

<p><a href=“http://i40.■■■■■■■.com/2vc935f.jpg[/url]”>http://i40.■■■■■■■.com/2vc935f.jpg&lt;/a&gt;&lt;/p&gt;

<p>Again, thank you in advance</p>

5

<p>This is a problem of draws. If I picture one band as a ball, here’s how it would work :</p>

<p>pick one ball. Possible picks : 6. Remaining balls : 5
pick another one. Possible picks:5. Remaining : 4.</p>

<p>And so on. every one of the first 6 picks will result in one of the 5, which will result in one of the four, and so on.</p>

<p>In other words, it’s 6x5x4x3x2x1, which is 6!. This is called the factorial.</p>

<p>However, you can only use this rule when we are picking, but not putting the balls back in the box. Others methods should be taken when it comes to other kinds of exercises.</p>

<p>Another example: 6 cards. What are the possible combinations you can have if you pick each one of them individually and do not place it back in the deck. The answer is 6!=720.</p>

<p>If you still don’t get it, just look up factorials and combinations. You should be fine.</p>

6

<p>Thank you very much! I got the point, I guess I have to work it up now</p>

7

<p>Sure. Just PM me if something’s wrong with math. I’ll do my best to help.</p>

8

<p>

</p>

<p>You do, but you should stick to official questions released by the College Board. Do yourself a favor and stay away from synthetic tests. </p>

<p>Why waste your time?</p>

9

<p>Using prep books other than CB is usually not a bad idea. However, ones with lots of mistakes or poorly written questions should be avoided. It’s a shame that many test-prep books have so many mistakes in their problems.</p>

10

<p>“Using prep books other than CB is usually not a bad idea.”</p>

<p>For most people, preparing for the SAT presents a challenge. Isn’t it hard enough to master the material and master the SAT’s particular way of presenting the material without also having to worry about whether the problems you are having are due to your own weaknesses or the poor quality of the book you are using? Even if 90% of the items are sufficiently SAT-like (and it takes a lot of experience to make that judgment), the 10% that are not will cause you unnecessary stress and wasted time as you struggle to master a nuance that turns out to be FAKE!!! I’ve always known that this is true for math, but I can see that it is true for verbal as well. Do you know how many threads here have wasted time and angst dissecting some sentence-error from some bogus source? </p>

<p>Same thing applies to math. Lots of threads here waste time and energy with fake questions. To find a thread like that…oh, wait: THIS is a thread like that! I am (obviously) a fan of using non-college-board books to learn the strategies and tricks and to review the content. But when it comes time to practice, there are enough real tests LEGALLY available to do a thorough and sane job preparing. </p>

<p>I know I won’t convince everyone. But I wish it could become standard procedure here that if you post a question from a fake source, you identify it as such immediately so that those who choose to ignore such material can avoid getting sucked in.</p>