Math Q's

<ol>
<li><p>A group of 30 people were surveyed at an amusement park. Of these, 22 liked water rides, 16 liked roller coaster rides, and 10 people like both water rides and roller coaster rides. How many people surveyed likes neither?
A)2
B)6
C)10
D)14
E)16
*so, this q. completely confused me, maybe I had a dumb moment (ans: A)</p></li>
<li><p>The surface of a 3-dimensional solid consists of faces, each of which has the shape of a polygon. What is the least number of such faces that the solid can have?
A) 2
B) 3
C) 4
D) 5
E) 6
(i was thinking cylinder, so B...no ans: C)</p></li>
<li><p>At a party there was one pizza for every 3 people one salad for every 6 people, and one cake for every 8 people. If the total number of pizzas, salads, and cakes was 'n', how many people were at the party?
A) 8n/5
B) 3n/2
C) 7n/4
D) 2n
E) 9n/4
(ans: A)</p></li>
<li><p>In this following equation, 'x' and 'k' are positive numbers and 0 < a < x. Which of the following must be equal to 'x'?</p></li>
</ol>

<p>EQUATION: (x - a)^5 = (x - a) ^k^4.........x - a in brackets, to the power of k, and k is raised to the power of 4.
A) k
B) k - a
C) k + a
D) a^4
E) k^4 + a
(ans: C)</p>

<p>20.
So, they give you a pic, but i'll explain it. There is a 3x3 square. In the center of that square is a 1x1 square, around which are made of 4 2x1 rectangles....forming a 3x3 square. </p>

<p>If a rectangular section of floor that is 24''x15'' must be covered with this pattern, with no overlap, how many tiles will be used?
A) 40
B) 80
C) 160
D) 200
E) 240
(i put a, which is wrong. why is it wrong? 24'' means 8 of these squares across....and 15'' means 5 downwards. so 8x5=40....seems too simple, but i dont know why it's wrong! ANS: D)</p>

<p>these were PSAT q's by the way :S. This is the most i've ever missed in an entire math portion of a test, let alone one section!</p>

<p>I’ll start from the bottom.</p>

<ol>
<li>Each 3" x 3" tile contains 5 more tiles (the rectangles and the small square). The actual number of tiles is 40 * 5, which is 200.</li>
</ol>

<p>I’m not sure about 19; I’ll keep thinking about it.</p>

<ol>
<li>You find the LCM (Least Common Multiple) of 3, 6, and 8. That number turns out to be 24, which is the number of people. Based on the number of people there, find the number of pizzas, salads, and cakes (based on the information). There are 8 pizzas, 4 salads, and 3 cakes. In total, there are 15. The answers given to you are looking for the number of people (24) in terms of the total number of food items (15). The answer is 24/15, which reduces to 8/5.</li>
</ol>

<ol>
<li>A group of 30 people were surveyed at an amusement park. Of these, 22 liked water rides, 16 liked roller coaster rides, and 10 people like both water rides and roller coaster rides. How many people surveyed likes neither?
A)2
B)6
C)10
D)14
E)16</li>
</ol>

<p>22 liked water rides
-10 liked water and roller coaster
12 liked ONLY water rides</p>

<p>16 liked coaster rides
-10 liked roller coaster and water
16 liked ONLY coaster rides</p>

<p>16+12 = 28</p>

<p>28 people liked at least one</p>

<p>30 - 28 =
2 people liked neither. (A)</p>

<ol>
<li>The surface of a 3-dimensional solid consists of faces, each of which has the shape of a polygon. What is the least number of such faces that the solid can have?
A) 2
B) 3
C) 4
D) 5
E) 6</li>
</ol>

<p>A polygon is two dimensional. The minimum amount of sides it can have is three.</p>

<p>A 3D shape is a polygon with depth. That adds another side. That makes the minimum amount of sides 4. (C)</p>

<p>Can you imagine a 3D shape with 2 or 3 sides? Cut up some paper and see if you can make one.</p>

<p>Tip: you can’t.</p>

<ol>
<li>(x-a)^5 = (x-a)^k^4</li>
</ol>

<p>Divide both sides by (x-a), this gives you: (x-a)^4 = k^4</p>

<p>Now take the 4th root of both the sides, this give you x-a = k, so x = k + a.</p>

<p>From: <a href=“http://talk.collegeconfidential.com/sat-preparation/404545-math-question.html[/url]”>http://talk.collegeconfidential.com/sat-preparation/404545-math-question.html&lt;/a&gt;&lt;/p&gt;

<p>

</p>

<p>You got the right answer, but your work is wrong I think.</p>

<p>The 16 - 10 = 6 only liked roller coasters.</p>

<p>So then you do 12 + 6 = 18 liked at least one.</p>

<p>Then we have to add back in the people who liked both so we do:
18 + 10 = 28</p>

<p>And subtract the 30 - 28 = 2 to get A.</p>

<p>Just clearing it up because it confused me heh :D</p>

<p>Yeah, sorry, I noticed that lol.</p>

<p>wow, thanks for the help everyone. do you think these questions were a little hard? all of them were in one section, and there were a couple other tough ones. seemed like a harsh section to me lol.</p>

<p>Seems like a pretty difficult section to me. The (x-a) question (#19) and the polygon question (#17) stumped me for quite a while. I don’t think I understand 17 yet (though I’m not much of a spatial reasoning person). #20 is very sneakily worded, but 7 and 18 aren’t too bad.</p>

<p>I understand why I was stumped about question 19.</p>

<p>You copied it wrong.</p>

<p>It’s (x-a) MULTIPLED BY k^4, not (x-a)^k^4.</p>

<p>^perhaps, but i looked it over and honestly, the K is smaller than the other variables (smaller than it should be), yet a little too big to be an exponent lol. confusing, but i guess its supposed to be multiplied.</p>

<p>did anyone understand how to do number 18?</p>

<p>

</p>

<ol>
<li>At a party there was one pizza for every 3 people one salad for every 6 people, and one cake for every 8 people. If the total number of pizzas, salads, and cakes was ‘n’, how many people were at the party?</li>
</ol>

<p>Based on the information, you know, by finding the LCM(24) of the three numbers given, that for every 24 people you have 8 pizzas, 4 salads, and 3 cakes, and that because the number you found was the LCM, 24 is the lowest number of people for which the number of each type of food will be an integer. That means that for every 24 people, the total number of food items will be 15. From the problem, you know the total number of food items, so you can take the fraction 24 people/15 food items = 8 people/5 food items and multiply it by (n food items) to obtain the answer, which should be (8n/5) people.</p>

<p>oh cool thanks, i get what you did but for the answer why did you take 24/15 to find the total amount of food?</p>

<p>There are 15 food items for every 24 people. If you divide both numbers by 15, you get 1 food item for every 24/15 people, and multiplying both by n gives you n food items for every 24n/15 people(which simplifies to 8n/5).</p>

<p>Does that make it any clearer?</p>

<p>hey guys… I know this is an old thread but I stumbled upon question 20 of this section
and I didn’t understand the explanation for it… can anyone help plz?</p>

<p>The entire figure of question number 20 is equal to 3 x 3 = 9 in area. BUT, it is not only one tile, it is five tiles. So if you got the answer as 40, then you were close. Multiply those 40 tiles by 5, because there are 5 tiles in each one, so you should have 200 tiles now.</p>

<p>oh! didn’t notice that there were 5 of them. thanks, Sir! ;)</p>