sat math help !!

Test Preparation SAT Preparation
1

<p>help please with explination
- the average ( arthematic mean ) of the test scores of a class of p students is 70 , and the average of the test scores of class n students is 92 . when the scores of both classes are combined , the average score is 86 what is the value of P
?</p>

2

<p>the smith metal company’s old machine makes 300 bolts per hour , it’s new machine makes 450 bolts per hour . if both machines begin running at the same time , how many minutes will it take the two machines to make a total of 900 bolts ??</p>

3

<p>Hi!
First question: the total score of two classes is 70p+92n. Then the average score of two classes is (70p+92n)/(p+n)=86. Calculate the equation, you can get 70p+92n=86p+86n, 6n=16p,p/n=3/8
Second question: assume it needs to take x hours. 300x+450x=900, x=1.2 hours=72minutes.
Glad to help~</p>

4

<p>thanks @quanlude and what’s about the second one ??</p>

5

<p>Google!</p>

<p><a href=“http://talk.collegeconfidential.com/sat-act-tests-test-preparation/78767-help-question-official-sat-blue-book.html[/url]”>http://talk.collegeconfidential.com/sat-act-tests-test-preparation/78767-help-question-official-sat-blue-book.html&lt;/a&gt;&lt;/p&gt;

6

<p>If we assume it needs to take x hours, the old machine can produce 300x bolts in x hours, and the new machine can produce 450x bolts in x hours. Because they are running at the same time, so they can produce 300x+450x bottles in total, which means 900=300x+450x, x=1.2 hours. because 1 hour=60 minutes so 1.2 hours=72 minutes.
Hope it will help~</p>

7

<p>Hi 16, sorry I can’t send you private message because I don’t have 15 posts.
No, I will not take Dec tests. I have taken it three times and I am sick of doing it again…
But I am happy to do any SAT math questions~</p>

8

<p>Can you make flashcards for math SAT study?</p>

9

<p>How high a level of math does SAT include</p>

10

<p>how to solve tis ? from oct. 2011 exam .

  • for all positive integrs x , the function f id defined by f(x)=(1/a power 4 )power x , where a is constant greater than 1. wich of the following is equivalent to f(2x) ?</p>
11

<p>what are the answers?</p>

12

<p>the answer for the last one will be (f(x))power2 .</p>

13

<p>Subsititute 2x for x in f(2x) equation, we can get f(2x)=(1/a^4)^(2x)=((1/a^4)^x)^2 (Change the order of power doesn’t matter, for example x^(ab)=(x^a)^b=(x^b)^a) Then because f(x)=(1/a^4)^x, f(2x)=f(x)^2.
“^” this sign means power.
Hope I am clear~</p>

14

<p>I don’t know how to campare the difficult level because I don’t know about American high school math level. But generally, SATI math is eaiser than SATII math and is eaiser than AP calculus.
The sad thing is I don’t know how to make flashcards T^T but if you post questions here, I’m happy to answer them.</p>