<p>Please, somebody must tell me that the sample question under the section “picking numbers”
cannot be correctly solved. It makes absolutely no sense to me! </p>
<p>[SparkNotes:</a> SAT Subject Test: Math Level 2: Math IIC Algebra Strategies](<a href=“SparkNotes: Today's Most Popular Study Guides”>SparkNotes: Today's Most Popular Study Guides)</p>
<p>I would say j = (vp - mv)/mp.</p>
<p>I know, they plug in numbers to solve that question. But somewhere must be a mistake in this question. They say D is correct because it is the choice which 10 results when you plug in their values. If I plug in their values in D I get 5 x 100 - 10 x 100 = 500, not 10…</p>
<p>Please enlighten me. Maybe I just worked too long, but that really freaks me out…</p>
<p>Thanks!</p>
<p>^
I checked all off the answer choices and none of them is working! Can somebody confirm this?</p>
<hr>
<p>I also found this on SparkNotes, which is also not correct:</p>
<p>The expression simplifies further:</p>
<p>4x(x^2-2+1) = 4x(x-1)^2</p>
<p>enlighten me, again! </p>
<p>but I am pretty sure that 4x(x^2-1) and 4x(x-1)^2 are two different equations!</p>
<p>P.S. Is SparkNotes notorious for making such careless errors? :(</p>
<p>you’re totally right, it should be v/m - v/p, or v(p-m)/mp.</p>
<p>also, that method for “picking numbers” isn’t very helpful, so I suggest you don’t practice it. It wastes too much time.</p>
<p>I have been working my way through the SparkNotes review book and tests as well, and yes, I’ve been finding quite a few mistakes. Sometimes I can figure out what they really meant (for example, they probably meant 4x(x^2-2x-1), which would indeed factor to 4x(x-1)^2), but sometimes they’re just plain wrong. When taking a practice test for Biology yesterday, it literally gave me a message that said “B is not the correct answer. You should have selected B.” I wouldn’t worry about it too much. The principles that they’re teaching are sound even if the examples and problems aren’t necessarily.</p>