Best riddles

logic

A liar and a truth teller

You are walking down a path when you come to two doors. Opening one of the doors will lead you to a life of prosperity and happiness, while opening the other door will lead to a life of misery and sorrow. You don't know which door leads to which life. In front of the doors are two twin brothers who know which door leads where. One of the brothers always lies, and the other always tells the truth. You don't know which brother is the liar and which is the truth-teller. You are allowed to ask one single question to one of the brothers (not both) to figure out which door to open. What question should you ask?
Ask "If I asked your brother what the good door is, what would he say?" If you ask the truth-telling brother, he will point to the bad door, because this is what the lying brother would point to. Alternatively, if you ask the lying brother, he will also point to the bad door, because this is NOT what the truth-telling brother would point to. So whichever door is pointed to, you should go through the other one.
84.15 %
44 votes

logic

The Two Barbers

There is a small town in the midwest with exactly 2 barbershops, one on each side of town. The barbershop on the west side of town is pristine. Its floors are spotless, the windows are always perfectly clear, and the air always smells fresh. The barber has a friendly smile, shined shoes, a well-groomed head of hair, and a fancy shirt. The barbershop on the east side of town is a mess. Its floors and windows are dirty, and the air smells of garbage. The barber always has a grimace on his face. His skin is oily, his hair is short and ragged, and he has food on his clothes all the time. A man travelling through the town realizes he needs a haircut. Knowing the stories of the two barbers, the man decides to go to the dirty barbershop on the east side of town. Why does he do this?
Because there are only two barbers in the town, the barbers must cut each-other's hair. The barber on the west side of town has a nice haircut, so the east-side barber must be a good barber. On the other hand, the barber on the east side of town has ragged hair, meaning the west-side barber must not be very good. So the man goes to the east-side barber to get a better haircut.
84.15 %
44 votes

logic

Course of expensive medication

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?
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 Cirate 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.
83.96 %
52 votes

cleanlogicshort

Four daughters

Mr. Smith has 4 daughters. Each of his daughters has a brother. How many children does Mr. Smith have?
He has 5 children, all of the daughters have the same 1 brother.
83.88 %
60 votes