Math brain teaser

<p>I moved during 10th grade lol and I only had a 90%.</p>

<p>holy hell some of those questions are easy!</p>

<p>LOL … go to the ask and discuss questions section there :slight_smile: Those are just some new users .</p>

<ul>
<li>I had 86% in grade 10 lol</li>
</ul>

<p>does IIT accept transfers? Anyway where you applying in the US?</p>

<p>I think it does, and it has masters too, but I’m not sure of the procedure for transfer.
I’m applying ED dartmouth, yale, princeton, harvard, MIT, SUNY plattsburgh, and Colgate. MY list is built on the fact that I require lots of fin. aid, that too as an international.
and ED dartmouth because I’ll have the highest chance there compared to the rest top schools… Since I’m dropping a year, I have to go with playing as safe as possible else I’ll be forced to join a local/regional college here itself lol.</p>

<p>no intls can go to IIT?</p>

<p>Are you an NRI (non-resident Indian) ? I can’t recollect having seen any international at IIT… But maybe NRIs can apply … check out their websites.</p>

<p>i am NRNI (non-resident non-indian) :(…</p>

<p>lol…Still, go through their sites.</p>

<p>C+H=1.5
C=H=3/4
C/2+2H=3/8+3/2=3/8+12/8=15/8=1.875</p>

<p>Where C is the (originally) whole crab and H is the half crab.</p>

<p>I add an amusing problem I saw on math team:</p>

<p>If a 100 lbs pile of coconuts that is 99% water by weight is reduced to 50 lbs by removing water what percentage is the 50 lbs pile of water by weight?</p>

<p>98%
1 pound from the 100 isn’t water, only water is taken out so 1 pound stays</p>

<p>I don’t like that problem with the goat. It combines two options, being door 2 and 3 if the car is behind door 1 saying that either will be chosen randomly. If you take these options into account, both remaining doors are given a 50% chance of having the car behind.</p>

<p>I don’t get the question, please rephrase lol. According to your q the % of the 50 lb pile would be 50.5% in relation to the total water in the system. Is that what the question is asking?</p>

<p>clockwork:</p>

<p>Read [Monty</a> Hall problem - Wikipedia, the free encyclopedia](<a href=“Monty Hall problem - Wikipedia”>Monty Hall problem - Wikipedia)</p>

<p>tamarind: the total water of the system isn’t what’s being asked. It asks for the % of the 50 lbs pile that is water by weight. (hint: Clockwork is dead on in with the simple solution)</p>

<p>"clockwork:</p>

<p>Read Monty Hall problem - Wikipedia, the free encyclopedia"</p>

<p>I’ve read it, and that’s where my complaint comes from. I do understand what they’ve done, but I don’t like how they combined two possible solutions. </p>

<p>There’s one being that the car is behind door 1, and either door 2 or 3 must be opened. It should be split up into the car is behind door 1, and door 2 must be opened; also, the car is behind door 1, and door 3 must be opened. I hope that gives better insight as to what I’m thinking.</p>

<p>clockwork, if we assume the car is behind door 1, and door 1 is the one you chose, (and of course the assumptions that the host knows which doors contain what, must open a door with a goat, and in this case must randomly choose between 2 and 3) then we can combine doors 2 and 3 because it doesn’t matter which door is opened nor does it matter which door you switch to because if you initially chose the car, switching will always cause you to lose. Given that only 1/3 of the time, switching will cause you to lose, that means 2/3 of the time switching will cause you to win.</p>

<p>I never knew for sure that the host knowing or not knowing influences the problem, but I always suspected that it did. Pretty sure I’ve often heard people phrase it as “the host randomly chooses to open one of the other doors and a goat is revealed.” Funny how in that situation, switching does not increase your odds, when I’m pretty sure the question asker has always insisted it increased your chances.</p>

<p>clockwork: I also dislike the counting solution to the problem, but the use of Bayes’ theorem makes the rigor of the proof better. [Bayes</a>’ theorem - Wikipedia, the free encyclopedia](<a href=“Bayes' theorem - Wikipedia”>Bayes' theorem - Wikipedia) this is the Bayes’ theorem page that has a nice write up on the Monty Hall problem and also explains (somewhat) the basics of Bayes’ theorem. This is, in my opinion, much nicer than the use of counting.</p>

<p>Well, Bayes theorem is extremely important in probability!</p>

<p>I love how this has come up in like 40 convos today. i had to explain it to people after we watched 21!</p>

<p>If a 100 lbs pile of coconuts that is 99% water by weight is reduced to 50 lbs by removing water what percentage is the 50 lbs pile of water by weight?</p>

<p>100 lbs pile –> 99 lbs water
50 lbs pile –> 49 lbs water
49/50 = 98/100 = 98%</p>