Blue Pill Problem
Logic puzzles require you to think. You will have to be logical in your reasoning.
You've been placed on a course of expensive medication in which you are to take one tablet of Sildenafil and one tablet of Citrate daily. You must be careful that you take just one of each because taking more of either can have serious side effects.
Taking Sildenafil without taking Citrate, or vice versa, can also be very serious, because they must be taken together in order to be effective. In summary, you must take exactly one of the Sildenafil pills and one of the Citrate pills at one time. Therefore, you open up the Sildenafil bottle, and you tap one Sildenafil pill into your hand. You put that bottle aside and you open the Citrate bottle. You do the same, but by mistake, two Citrates fall into your hand with the Sildenafil pill.
Now, here's the problem. You weren't watching your hand as the pills fell into it, so you can't tell the Sildenafil pill apart from the two Citrate pills. The pills look identical. They are both the same size, same weight (10 micrograms), same color (Blue), same shape (perfect square), same everything, and they are not marked differently in any way.
What are you going to do? You cannot tell which pill is which, and they cost $300 a piece, so you cannot afford to throw them away and start over again. How do you get your daily dose of exactly one Sildenafil and exactly one Citrate without wasting any of the pills?
Answer
Carefully cut each of the three pills in half, and carefully separate them into two piles, with half of each pill in each pile. You do not know which pill is which, but you are 100% sure that each of the two piles now contains two halves of Citrate and half of Sildenafil. Now go back into the Sildenafil bottle, take out a pill, cut it in half, and add one half to each stack. Now you have two stacks, each one containing two halves of Sildenafil and two halves of Citrate. Take one stack of pills today, and save the second stack for tomorrow.
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Comments
lauramarie
Jun 10, 2003
 Excellent! 
(user deleted)
Jun 10, 2003
 thats good i would have never thought oph that so i would either be dead or out $900 
hersheykiss8908
Jun 12, 2003
 this is a very good brain teaser. It's solution could be helpful in real life, too. 
hotsteppa
Jun 18, 2003
 The two pills cause quite a rush when put together... that's why they call it Viagra! 
Deflected
Jun 21, 2003
 Love it! It is a great brainteaser! 
dakini
Jun 26, 2003
 Great teaser! I never would have thought of that one!!

jimbo
Jul 06, 2003
 If they cost $300 each then you would know exactly how many were in the bottles. Count the pills remaining in each bottle to see which bottle had one less pill! 
Gerd
Aug 12, 2003
 Super! That's real logic. It's like the riddle with the two blind men and their socks.@jimbo:imagine the bottles containig each two pills at the beginning of the procedure. And then only one bottle has a remaining pill. What does it help? 
ASHBASH
Aug 25, 2003
 YOU WOULD HAVE TO KNOW WHICH PILL WAS WHICH TO DIVIDE THEM CORRECTLY!
COUNT THE PILLS WOULD BE EASIER. 
Gerd
Aug 26, 2003
 ejasami's answer is absolutely correct! Counting the pills doesn't work. Taking the 4th pill, we get the dose for today and tomorrow. After cutting a pill you immediately get one half and put aside the other half. After the 4th pill you got your correct dose for today, and the other 4 halfs are for tomorrow.Top riddle!!! 
curtiss82
Jan 21, 2004
 Yeah, counting the pills doesn't work. You already know that you have two of one kind of pill and one of the other, it's just that you don't know which one is which and you don't want to waste any of them. This is a great teaser. 
Drakar
Feb 04, 2004
 Then you can sue the companies for making them look so alike, capable of causing a serious accident... 
Justal
Nov 22, 2004
 It doesn't work because you can end up with 1 and 1/2 doses of
Citrate in one pile and 1/2 of Citrate and full dose of Sildenafil
in the other.
Spilting another Sildenafil will not solve the problem 
chuckelect
Mar 14, 2005
 this is an outstanding logic teaser!! and the answer is correct. 
peanut
Sep 01, 2005
 Brilliant! This is an excellent teaser. I do agree though that counting the pills left in the bottle WILL work and is the more obvious answer (to us lesser mortals with lower brain capacities!) 
boodler
Feb 16, 2006
 This is why each of the 7 pills I take each day are totally different to each other! 
grungy49
Dec 17, 2006
 So.. what if you get two halves of the same pill today? Will you be able to survive until tomorrow? Are they powerful enough?
Just kidding, cool teaser 
spinnercat
Aug 15, 2007
 i said to add one more sildenafil pill to the pile, then grind them up and mix up the mixture. Split it in half, and put one pile of the powder into a drink, and drink it. Save the other pile for tommorow. 
calmsavior
Oct 24, 2007
 Not so sure about that, there might be much more of a one pill in one pile than the other. 
Oinky08
Jan 07, 2009
 counting makes it easier though... 
MikeG
Oct 09, 2011
 Counting the remaining pills does not help you. You already know that there are two citrate pills, and therefore you have one less pill in the citrate bottle. What do you do now  pick one at random from your hand and put it back in the bottle, hoping that you chose correctly? Nope. 
noobkid
Oct 12, 2011
 Er....much more easy solution  take out all the pills, perceive the deficit in numbers for each bottle. If there is a deficit in one of the bottles, then that would be the pill you took two out of. 
noobkid
Oct 12, 2011
 lol nvm i was wrong 
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