Long hard clean riddles for teens

cleanlogicsimple

A young peasant wanted to marry the king's daughter. The king didn't like the idea of his daughter marrying a peasant, but he wanted to appear fair in front of his subjects. The king said that he would put two pieces of paper into a hat, one reading "exile" and the other reading "marriage". Later that day, the peasant overheard the king saying that both pieces of paper would read "exile", thus ensuring that the peasant would be out of his way for good. The peasant remained undaunted and, as arranged, arrived at the king's court where a large crown gathered for the big event. The peasant then did something that assured him the hand of the king's daughter. What did he do?
The peasant picked one of the pieces of paper and tore it up. He then asked the kind to show him the other piece of paper which, of course, said EXILE. The king, not wishing to appear fraudulent in front of his subjects, granted that the piece of paper the peasant had picked must have said MARRIAGE.
75.08 %
124 votes
logicmathsimplecleanclever

There are 100 ants on a board that is 1 meter long, each facing either left or right and walking at a pace of 1 meter per minute. The board is so narrow that the ants cannot pass each other; when two ants walk into each other, they each instantly turn around and continue walking in the opposite direction. When an ant reaches the end of the board, it falls off the edge. From the moment the ants start walking, what is the longest amount of time that could pass before all the ants have fallen off the plank? You can assume that each ant has infinitely small length.
The longest amount of time that could pass would be 1 minute. If you were looking at the board from the side and could only see the silhouettes of the board and the ants, then when two ants walked into each other and turned around, it would look to you as if the ants had walked right by each other. In fact, the effect of two ants walking into each other and then turning around is essentially the same as two ants walking past one another: we just have two ants at that point walking in opposite directions. So we can treat the board as if the ants are walking past each other. In this case, the longest any ant can be on the board is 1 minute (since the board is 1 meter long and the ants walk at 1 meter per minute). Thus, after 1 minute, all the ants will be off the board.
74.89 %
100 votes
cleanpoemswhat am I

For thousands of years, Seen only in tale. The wind as a sail, For one thunderous gale. Shiny stores rich in lore, The burning temper, like Earth's core. What am I?
Dragon
74.88 %
177 votes
cleanlogicsimple

Two men are in a desert. They're both wearing backpacks. One of the men is dead. The man who is alive, has his pack open. The dead man's pack is closed. What is in their packs?
A parachute.
74.04 %
83 votes
logicsimpleclean

You're standing in front of a room with one lightbulb inside of it. You cannot see if it is on or off. Outside the room, there are 3 switches in the off positions. You may turn the switches any way you want to. You stop turning the switches, enter the room and know which switch controls the lightbulb. How?
You turn 2 switches "on" and leave 1 switch "off" and wait about a minute. Then enter the room, but just before you enter, turn one switch from "on" to "off". Once in the room, feel the lightbulb - if it is warm, but off, it has to be the last switch you turned off. If it is on, it has to be the switch left on. If it is cold and is off, it has to be the switch you left in the off position.
74.03 %
101 votes
logicsimpleclean

Six glasses are in a row. The first three are filled with milk and the last three are empty. By moving only one glass, can you arrange them so that the full and the empty glasses alternate?
Just pour full glass of milk at 2nd position in 5th glass(empty) and keep that empty glass back at 2nd position. Then full and empty glasses are at alternate positions.
73.40 %
72 votes
logicmathclean

You are visiting NYC when a man approaches you. "Not counting bald people, I bet a hundred bucks that there are two people living in New York City with the same number of hairs on their heads," he tells you. "I'll take that bet!" you say. You talk to the man for a minute, after which you realize you have lost the bet. What did the man say to prove his case?
This is a classic example of the pigeonhole principle. The argument goes as follows: assume that every non-bald person in New York City has a different number of hairs on their head. Since there are about 9 million people living in NYC, let's say 8 million of them aren't bald. So 8 million people need to have different numbers of hairs on their head. But on average, people only have about 100,000 hairs. So even if there was someone with 1 hair, someone with 2 hairs, someone with 3 hairs, and so on, all the way up to someone with 100,000 hairs, there are still 7,900,000 other people who all need different numbers of hairs on their heads, and furthermore, who all need MORE than 100,000 hairs on their head. You can see that additionally, at least one person would need to have at least 8,000,000 hairs on their head, because there's no way to have 8,000,000 people all have different numbers of hairs between 1 and 7,999,999. But someone having 8,000,000 is an essential impossibility (as is even having 1,000,000 hairs), So there's no way this situation could be the case, where everyone has a different number of hairs. Which means that at least two people have the same number of hairs.
73.22 %
67 votes
interviewlogiccleansimple

You are standing before two doors. One of the path leads to heaven and the other one leads to hell. There are two guardians, one by each door. You know one of them always tells the truth and the other always lies, but you don’t know who is the honest one and who is the liar. You can only ask one question to one of them in order to find the way to heaven. What is the question?
The question you should ask is "If I ask the other guard about which side leads to heaven, what would he answer?" It should be fairly easy to see that irrespective of whom do you ask this question, you will always get an answer which leads to hell. So you can chose the other path to continue your journey to heaven. This idea was famously used in the 1986 film Labyrinth. Here is the explanation if it is yet not clear. Let us assume that the left door leads to heaven. If you ask the guard which speaks truth about which path leads to heaven, as he speaks always the truth, he would say "left". Now that the liar , when he is asked what "the other guard (truth teller) " would answer, he would definitely say "right". Similarly, if you ask the liar about which path leads to heaven, he would say "right". As the truth teller speaks nothing but the truth, he would say "right" when he is asked what "the other guard( liar ) " would answer. So in any case, you would end up having the path to hell as an answer. So you can chose the other path as a way to heaven.
71.87 %
101 votes
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