<p>If you already got an 800, why is this score so important to you? Most universities allow score choice.</p>
<p>(a+b)/2 = radical (axb)</p>
<p>which could be true?
a>0
a < 0
a =0</p>
<p>Also is it possible to solve for x if thy gve us to sides of a scalene triangle (not a right triangle) as equations involving x.</p>
<p>say one side is 5x-7
The other is 7x-3 (note these are just expressions I made up)</p>
<p>they also give u 2 angles. One is 70 other is 40</p>
<p>o.o</p>
<p>1) I’m assuming the ‘x’ is multiplication. a could be positive. Let a=b=1. (1+1)/2=1 and sqrt(1*1)=1. a can’t be negative since for the square root to exist, b would have to be nonpositive. But then (a+b)/2 is negative and sqrt(ab) is posititive (well at least nonnegative, allowing for the case b=0. In any event, they aren’t equal). a could be zero. Let a=b=0. (0+0)/2=sqrt(0^2). So only the first and third statements are true.</p>
<p>2) You can solve for x but this involves trigonometry that is beyond the level of the SAT.
Edit: technically you don’t have enough information. You also need to know what side is opposite what angle.</p>
<p>Finding sides and/or angles of an arbitrary triangle generally requires the Law of Sines or Cosines. This is not tested on the SAT, but it is tested on the ACT.</p>
<p>A little info about your problem above:</p>
<p>(a+b)/2 is the arithmetic mean of a and b </p>
<p>radical (ab) is the geometric mean of a and b.</p>
<p>Assume a, b nonnegative. Then the arithmetic mean is always greater than or equal to the geometric mean, and equality holds if and only if a = b. </p>
<p>@2200andbeyondXD</p>
<p>
</p>
<p>@DrSteve
Well guys… I was about to solve this by Sine rule but then realized something… that you’re given two angles… you can find the last angle. Once you find that you’ll realize it’s an isosceles triangle! But I think you have the values wrong over here or either have placed a wrong sign in one of those. since the answer was 6 i think.</p>
<p>Which section was Math experimental? tell me the last question/second last of the experimental section.</p>
<p>see the image below</p>
<p>
<a href=“http://i.imgur.com/5XXrOWZ.png”>http://i.imgur.com/5XXrOWZ.png</a>
</p>
<p>One can say that 7x-3>5x-7 for all positive x, so 7x-3 is opposite one of the 70 degree angles (so yes, I was wrong earlier). So we get sin(70º)/(7x-3)=sin(40º)/(5x-7) and i get x≈23.4.</p>
<p>But he mentions that it is a scalene triangle. How could it have angles 70, 70, 40 if that measures out to be an Isosceles?</p>
<p>But he mentions that it is a scalene triangle. How could it have angles 70, 70, 40 if that measures out to be an Isosceles?</p>
<p>Level 3 Algebra</p>
<ol>
<li>For all numbers a and b, let a#b = a^2 - 3ab^2. What is the value of |5#(2#1)| ?</li>
</ol>
<p>I have a problem regarding maths specially in Graphs,Functions and Probability.
What should I do in order to get better in these criterias? @DrSteve </p>
<p>2#1=2^2-3<em>2</em>1^2=4-6=-2.
5#(-2)=5^2-3<em>5</em>(-2)^2=25-3<em>4</em>5=25-60=-35.
|-35|=35.</p>
<p>@Random That’s right.</p>
<p>@StarAim Sounds like you’re having trouble with mostly Level 4 and 5 problems (unless your probability is really weak). You will get better at Level 4 and 5 problems by practicing Level 4 and 5 problems. Try to solve each problem in at least 2 different ways, and make sure you redo problems you get wrong every few days until you can get them right on your own. </p>
<p>@DrSteve thanks for the advice. My probability is not that weak but I m inconsistent.</p>
<p>During a sale, for every three shirts purchased at regular price, a customer can buy a fourth at 50% off. If the regular price of a shirt is $4.50, and the customer spent $31.50 on shirts, how many shirts did the customer purchase?</p>
<p>The price of four shirts is 3<em>4.50+2.25 (the fourth one is half off), which is $15.75. This is half of the $31.50, so 4</em>2=8 shirts were bought.</p>
<p>Thank you! That makes a lot more sense then plugging in all choices.</p>
<p>For another problem from the PR PSAT book, it says that </p>
<p>Sally, Abdul, and Juanita stuff a certain amount of envelopes. Alone, Sally could stuff all envelopes in exactly 3 hrs, Abdul in 4 hrs, and Juanita in 6 hrs. If the three work together at these rates, what fraction will be stuffed by Juanita?</p>
<p>Answer</p>
<p>tau628
12:33PM in SAT Preparation
The answer is 2/9, which I got by supposing there are 12 envelopes–> converting each person into a rate --> setting up a proportion relating the combined rate to 12 letters / x hrs and finding out that in total the combined time would be 12/9 hrs.</p>
<p>Then, I used dimensional analysis to figure out that Juanita does 2.6666666667 envelopes during that time. 2.666666667/12 then = .222222222 which I recognized to be 2/9. But this took at least a minute and a half–any better solutions?</p>
<p>The fraction each person can finish after time t is t/3, t/4, and t/6 for Sally, Abdul, and Juanita, respectively. Say it takes time T for them to finish the job (you can solve for T but there’s no need to). Then Sally stuffed T/3, Abdul stuffed T/4, and Juanita stuffed T/6. Find (T/6)/(T/3+T/4+T/6)=2/9.</p>