PSAT 2010 Wednesday General Discussion

<p>@dapotatoman: My friends all said they got 1/5…I got 1 but I’m willing to bet that I’m wrong because my math skills aren’t that great.</p>

<p>^Do you remember the question?</p>

<p>Sorry, I don’t. I saw some people discuss it in the math thread though. Maybe you could check there.</p>

<p>I got 1. I double checked, too. How many friends do you have (that got 1/5)?</p>

<p>xrad5=5y, find yrad5/5x</p>

<p>I got 1/5.</p>

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</p>

<p>You were given that 5y = x<em>sqrt(5), and you had to find the value of y</em>sqrt(5)/(5x) - I may have flipped my variables. You can manipulate 5y = x*sqrt(5):</p>

<p>5y = x<em>sqrt(5)
5y/(x</em>sqrt(5)) = 1
y*(sqrt(5))/x = 1</p>

<p>At this point you can see that the only difference between what you have—y<em>(sqrt(5))/x—and what you want—y</em>(sqrt(5))/(5x)—is a 5 in the denominator. If you multiply both sides by 1/5, you get this:</p>

<p>y*(sqrt(5))/(5x) = 1/5</p>

<p>which should give you the solution.</p>

<p>I asked 3 people after I saw the math thread…But I could have sworn that I got 1. Can anyone else comment on that question?</p>

<p>It was 1/5.</p>

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</p>

<p>Agreed. I don’t know exactly how I did this… I think I set it up so that x=5 and y=rad5, to fit the first equation, then (rad5)^2 divided by 5*5 equaled 5/25, or 1/5.</p>

<p>the solution being…1/5 or 1?</p>

<p>Wolfram Alpha declares the answer to be 1/5.</p>

<p>[xsqrt5=5y</a>, ysqrt5/5x - Wolfram|Alpha](<a href=“xsqrt5=5y, ysqrt5/5x]xsqrt5=5y - Wolfram|Alpha”>xsqrt5=5y, ysqrt5/5x - Wolfram|Alpha)</p>

<p>The consensus on CC appears to be 1/5.</p>

<p>Ohhhhhh crap. I just did it again. It is 1/5. I overlooked the 5 ;_;</p>

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<p>Well, you were trying to find the value of y<em>(sqrt(5))/(5x), and the equation you ended up with was y</em>(sqrt(5))/(5x) = 1/5. The answer is 1/5.</p>

<p>I didn’t see the question, but “believed to have been built” implies that there were two past tense events - believed, and built - which would take the Past Perfect Tense to show order in the past events…</p>

<p>Other grammar questions?</p>

<p>Didn’t see the buttress question either, but the logic of that sentence “evidence didn’t _____” buttress would work.</p>

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</p>

<p>Not true. In this case, “believed” is the past participle of “to believe”—the verb that determines tense is the verb that comes before “believed”, which is “is”. The present tense is being used to describe the time in which something “is believed”, and “to have been” is a perfect infinitive.</p>

<p>So is the consensus no error or “to be built?” I personally put “to be built” (because I was thinking “to have been built” or something like that).</p>

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<p>The consensus is that it should be “to have been built” instead of “to be built”, but there’s confusion about why.</p>

<p>edit: should I have said “it should be” or “it should have been”?</p>

<p>The consensus is that there is no consensus :D</p>