HARD ACT math Q SEE if YOU CAN SOLVE

Test Preparation
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<p>I have a math degree and I also thought that both 200 and 260 would be acceptable answers. Not sure under pressure that I would have been able to discern that 260 was the best answer, especially if I punted and got the answer by trial and error with the possible choices - i.e. 200 is the first answer in the list that could work, I would reason that there would only be one answer that would work, ergo I might go no further.</p>

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<p>A tenet of superior multiple-choices questions is to include the obvious TRAP answer. In the SAT, this answer is often the middle suggestion. In the case of averages, and especially speed average, the answer is often the simple average. And the statistics show that the poorly prepared student often picks that trap answer. </p>

<p>It is based on this that it is did not take any time at all to pick 260 and move on. Fwiw, take a final look at the words used in the question and notice the parallel construction of the sentences. Similar words have to relate to similar concepts.</p>

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<p>He averaged 190 seconds per lap … = Q? More than 1 lap?
Rusty averaged 180 seconds per lap … = More than 1 lap?
Began the last lap = Last or second lap?</p>

<p>Oh well, if I could not explain why this problem had only one solution and one that required no more than reading the question until now, I would not be able to do with 20 more posts. If you want to cling to the notion that an average of ONE number means something, so be it! </p>

<p>It is what it is. A real simple, really silly problem, with 260 as the answer to pick. Not 200!</p>

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<p>Another issue with the problem (this doesn’t concern the definition of “arithmetic mean”):</p>

<p>“Qualifying rounds” vs. “qualifying round.” It just seems that they could’ve worded the problem better.</p>

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<p>Is that the 1296 PR book really says? Or is that what the person who answered 200 (in error) on the yahoo forum said?</p>

<p>The question number 50 is on Page 35 and on page 427, the proposed answer starts with:</p>

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<p>Nuff said!</p>

<p>PS Fwiw, the answer provided by PR is not really satisfactory as they do NOT show how to arrive at 7 laps. It is, however, clear that they intended for the answer to be 260.</p>

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<p>xiggi - it looks as if they give some information before the problems to be used for several of them:

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<p><a href=“http://www.amazon.com/Practice-Questions-Edition-College-Preparation/dp/0307945707/ref=dp_ob_title_bk#reader_0307945707[/url]”>http://www.amazon.com/Practice-Questions-Edition-College-Preparation/dp/0307945707/ref=dp_ob_title_bk#reader_0307945707&lt;/a&gt;&lt;/p&gt;

<p>That certainly changes things.</p>

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<p>You are right. </p>

<p>Massaging the search inside feature a bit reveals the rest of the hidden text: “Rusty and Dale each drive 8 laps.” </p>

<p>X-posted before Sylvan’s added text.</p>

<p>PS The added instruction obviously make my comments about the proposed answer not being satisfactory. However, I still think that the problem was easy to solve as I described in the very early posts in this thread. Actually NOT being told there were 8 laps made it just a bit more interesting. :)</p>

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<p>Only 260 can be correct. The question implies the average of 180s before the last lap was from multiple laps (you won’t call it average if there is only one lap). Only if there were 2 total laps (180s in one lap and 200 in the second lap) can make the 200s in the final lap a correct answer. So only 260s can be correct.</p>