Hard Math Problem =(

<p>Thinking always worked just fine for me on the SAT I.</p>

<p>tokenadult's point is gr8.. thinking worked for him; for others memorizing might b perfect; for me i like to do both.. so i guess its all up to thhe individual and its high time we stop fighting over whether the xiggi technigue is better or ellen f's technique is better or whatever.
at the end of the day we goota do what suits us..</p>

<p>PS:XIGGI THAT SIMPLE RATE FORMULA OF YOURS HAS HELPED ME LOADS. CANT THANK U ENOUGH..</p>

<p>I don't know why all you people are so crazy about formulas. that is the thing i hate about american education, evry little detail are formulas, as ellen said, USE COMMON SENSE!!!!!!!!!! u know why? because when the problem changes a bit or when u forget the formula, u are DOOMED. but if you know how to get to that formula, its origins, u can almost solve any problem.</p>

<p>Memorizing formulas is not learning the stuff, you just copy and paste information rather then actually digesting it. </p>

<p>hope u guys change ur erroneous view of math</p>

<p>im amazed at people at tashin and ELLEN F.. they just know one thing about common sense and harp on the topic without paying any attention to the context. People, were talking about the SAT and not ur high school or college math. Why do u want to waste ur valuable tiem on ur so-called common sense approach when u can use the formula and save time on the problems..?????? come on guyz dont argue just for the sake of it..</p>

<p>skywalker: Read tashin's last post, and you'll see why he (she?) makes that point. A formula, most of the time, will apply to one specific type of problem. If you find a variation of the problem--what if there are two roundtrips instead of one?--it might stop working. And if you forget the formula and don't know how to think about the problem, you're in trouble.</p>

<p>Random note, not just directed at skywalker: There are a lot of interesting applications of the harmonic mean, including this problem (average speed at constant distance). Basically, to find a harmonic mean, you take the inverses of the numbers, average those, then take the inverse of the result. Look for this in application problems, and you might be surprised how often it turns up. (It also pops up in geometry once in a while, but you probably won't see those problems on the SAT. PM me if you want examples.)</p>

<p>GeorgeS..... I found out about that formula like a year ago... and it is sooo useful!!!!... It saves so much time........Man I love stuff like thath</p>

<p>ill admit u hav a point Sly...</p>

<p>where can i find the expedient way to derive this answer</p>

<p>The question is almost 10 years old and long forgotten. I’d suggest posting it as a new question if you’re interested.</p>