### Brain Teasers

# Blue Pill Problem

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?

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.Hide Answer Show Answer

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## Comments

Excellent!

Jun 10, 2003

thats good i would have never thought oph that so i would either be dead or out $900

this is a very good brain teaser. It's solution could be helpful in real life, too.

The two pills cause quite a rush when put together... that's why they call it Viagra!

Love it! It is a great brainteaser!

Great teaser! I never would have thought of that one!!

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!

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?

YOU WOULD HAVE TO KNOW WHICH PILL WAS WHICH TO DIVIDE THEM CORRECTLY!

COUNT THE PILLS WOULD BE EASIER.

COUNT THE PILLS WOULD BE EASIER.

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!!!

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.

Then you can sue the companies for making them look so alike, capable of causing a serious accident...

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

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

this is an outstanding logic teaser!! and the answer is correct.

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!)

This is why each of the 7 pills I take each day are totally different to each other!

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

Just kidding, cool teaser

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.

Not so sure about that, there might be much more of a one pill in one pile than the other.

counting makes it easier though...

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.

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.

Oct 12, 2011

lol nvm i was wrong

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