<p>I'm really irritated at myself that I cannot get this, but here it is.</p>
<p>Hose 1 fills up up a tank of water in t hours. Hose 2 fills up a tank of water in t/2 hours. Both hoses together fill up the tank in 12 hours. Find t." (Ans=30)</p>
<p>My answer is not 30. I'm getting 36.</p>
<p>I did- Let the total water be- x
Speed of filling water for first hose- x/t
Speed of second hose- x/(t/2) or 2x/t
Speed together= x/12
Eqn-
x/t + 2x/t = x/12 (cancelling t both sides)
1/t + 2/t = 1/12
3/t = 1/12
t= 36.
Please tell me if this is wrong and what the correct method is.
Thanks!</p>
<p>There might be an error in the question. I used a slightly different method and got the same answer. 36, that is.</p>
<p>IT IS! Yay! I thought something had seriously gone wrong with my brain and I couldn’t do such an obvious question. I tend to go wacky when test deadline approaches anyway.;)</p>
<p>I would still appreciate it if another poster could confirm though! :)</p>
<p>Is this an official Collegeboard question? If so, then I might be a little skeptical too because official collegeboard are VERY rarely, if ever, wrong. And where did you confirm the answer from? I can’t find any other method to attempt this question.</p>
<p>It was a November 2010 testing date question. I saw other CCers discussing it in the Discussion thread and everybody agreed that 30 is the answer. :(</p>
<p>MidnightMaruader has quoted the question here and he says that the answer is 36, there is a chance that the answer others are referring to is for some other question or Midnightmaruader quoted the question wrong.</p>
<p><a href=“http://talk.collegeconfidential.com/sat-preparation/1027501-november-2010-sat-international-5.html[/url]”>http://talk.collegeconfidential.com/sat-preparation/1027501-november-2010-sat-international-5.html</a></p>
<p>See? Almost everyone there says the answer for the “tank question” is 30. I think only Midnighmarauder got 36?</p>
<p>It’s confusing what they’re referring to, so that’s why I thought of asking for another opinion.
Thanks for your help! :)</p>
<p>Think about it, though. </p>
<ul>
<li><p>If Hose 1 fills up the tank in 36 hours, how much of the tank will it have filled in 12 hours? The answer is 12/36=1/3. </p></li>
<li><p>If Hose 1 fills up the tank in t = 36, it follows that Hose 2 fills it up in t/2 = 18 hours. How much of the tank will it then have filled up in 12 hours? 12/18 = 2/3. If Hose 1 fills up 1/3 and Hose 2 fills up 1/3 - the tank is full, and it follows that the two of them will have filled up the tank in 12 hours, when t = 36.</p></li>
</ul>
<p>Your math is correct perfectpixie, and although it’s nice to check your work afterwards (in fact you should check your work afterwards) this doesn’t mean you should doubt your work. Have faith in yourself and your abilities - that’s the most important thing, in my opinion.</p>
<p>Thank you for the encouraging words stevierimbad!
That is something I do not have. YES. Even in sucky SAT math 
But I think I will, atleast a little more tomorrow. Thanks! :)</p>