Gruber's Complete, some math questions

<p>The numbers: 20, 36 out of refresher part 1 test.</p>

<p>The problems:</p>

<ol>
<li>If it takes 16 faucets 10 hours to fill 8 tubs, how long will it take 12 faucets to fill 9 tubs?
I eventually figured out the right answer, but I didn't do it the way Gruber's showed. Gruber's had something about how if it takes 16 faucets ten hours to fill 8 tubs, one faucet would take
160 hours to fill them all. They have this proportion set up: </li>
</ol>

<p>16faucets/1faucet = xhours/10hours
Why doesn't 16/10hours = 1/xhours work? I know it doesn't, but why not? </p>

<ol>
<li>Is the same thing, with the same style solution.</li>
</ol>

<p>p.s. forgot one more question:14 out of the same set.
14. If 1" represents a thousand miles on a map scale, what would the be the representation on a map of a 16 million square mile area? I got the right answer, but I want to know why you couldn't work backwards :
1/1000miles = 1^.5 / 16mill ^.5 , to get rid of the square.</p>

<p>thanks!</p>

<p>I was able to solve both, I’m trying to write up the solutions (they’re a bit complex). What was the answer to the first one?</p>

<p>I solved them too. 20. was E. I just didn’t do it a prescribed.</p>

<p>what was the numerical answer for #20- just want to confirm before posting answer</p>

<p>What do you think of Gruber’s book, in general?</p>

<p>I’m finding quite a few errors in the book. And the practice test scores don’t seem to compare with those from other books like the Blue Book, Kaplan, etc. </p>

<p>I think Gruber’s has some good reviews and a some strategies that aren’t in other books, but the tests don’t seem as accurate, IMO.</p>

<p>E: 15 hours. Also, do you guys really follow the dumb table method in session 2 (rate, work, distance, etc.) </p>

<p>And I always can’t solve those “If Train A is going at 40mph on a 300mi stretch, and Train B is going the opposite way at 50mph, when do they meet?” How do you do those kinds of thigns? And I’ve heard Gruber’s problems are more difficult than the real thing, but does that apply only the practice tests at the end of the book?</p>

<p>Does anyone else think that some of the math explanations are hard to follow at times. Math is my worst subject and it might be just that it is only hard for me.</p>

<p>2nd page already? lebump</p>

<p>do you have to actually use Gruber strats on the practice session tests to gain in score using that book?</p>

<p>I don’t have Gruber’s…buuut,</p>

<p>is the answer to #14 sixteen (16) inches?
what i did was set the sides of the rectangular area to 4000 by 4000 miles. 4000 mi = 4 in so 4x4 = 16 inches?</p>

<p>as for #20
is it 7.5 hours? if 16 faucets need 10 hours to fill 8 tubs, then that means 2 faucets are in charge of 1 and 1 tub needs 1.25 hours each. so group 12 into 6 groups of 2, and 6x1.25=7.5? Lol iono.</p>

<p>16 square inches yeah. That actually makes a lot of sense, thanks!</p>

<ol>
<li>I think it was 15, so half way there…there must have been some error in there.</li>
</ol>