Three Rivers Riddle
There are three rivers and after each river lies a grave. A man wants to leave the same number of flowers at each grave and be left with none at the end. However, each time he passes through a river, the number of flowers he has doubles. How many flowers does he have to start with so that he is left with none at the end? And how many does he leave at each grave?
Hint:
This problem has an infinite number of solutions modeled by the equation 8a=7n, where a is the amount of flowers the man starts with and n is the number of flowers he leaves at each grave. The simplest and possibly trivial solution would be to start with 0 flowers and leave 0 flowers at each grave. A more significant solution would be to start with 7 flowers and leave 8 at each grave. Any positive integer multiple of this solution also satisfies the conditions. For example, the man starts with 14 flowers and leaves 16 at each grave; so, 14 doubles to 28, and 28-16= 12; 12 doubles to 24, and 24-16= 8; 8 doubles to 16, and 16-16= 0. The result is the same if the man starts with 21 flowers and leaves 24 flowers at each grave, or starts with 28 and leaves 32. Did you answer this riddle correctly?
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Flip The Switch Riddle
There is a prison with 100 prisoners, each in separate cells with no form of contact. There is an area in the prison with a single light bulb in it. Each day, the warden picks one of the prisoners at random, even if they have been picked before, and takes them out to the lobby. The prisoner will have the choice to flip the switch if they want. The light bulb starts off.
When a prisoner is taken into the area with the light bulb, he can also say "Every prisoner has been brought to the light bulb." If this is true all prisoners will go free. However, if a prisoner chooses to say this and it's wrong, all the prisoners will be executed. So a prisoner should only say this if he knows it is true for sure.
Before the first day of this process begins, all the prisoners are allowed to get together to discuss a strategy to eventually save themselves.
What strategy could they use to ensure they will go free?
When a prisoner is taken into the area with the light bulb, he can also say "Every prisoner has been brought to the light bulb." If this is true all prisoners will go free. However, if a prisoner chooses to say this and it's wrong, all the prisoners will be executed. So a prisoner should only say this if he knows it is true for sure.
Before the first day of this process begins, all the prisoners are allowed to get together to discuss a strategy to eventually save themselves.
What strategy could they use to ensure they will go free?
Hint:
Only allow one prisoner to turn the light bulb off and all of the others turn it on if they have never turned it on before. If they have turned it on before they do nothing. The prisoner that can turn it off then knows they have all been there and saves them all when he has turned it off 99 times. Did you answer this riddle correctly?
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Pounds Of Sugar Riddle
The grocer had ten customers, each wanting to buy a 2 pound bag of sugar. A 20 pound bag of sugar had been delivered that morning, but he had not yet divided it because he could only find the 5lb and 9lb weights. One of the customers, getting impatient, showed him the quickest way to measure the sugar with the two weights he already had. How did he do it?
Hint:
Weigh out 4 pounds of sugar with the 5lb and the 9lb weights in different pans of the scales. With the 4lb weight , weigh three more lots of 4 pounds each - the remaining sugar will also weigh 4 pounds. Divide each 4 pound portion equally on the two sides of the scales. Did you answer this riddle correctly?
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Savor The Flavor Riddle
Discovered in Africa, I spread like a tide to become a hot staple known the world wide.
A necessity to some, a treasure to many, I'm best enjoyed among pleasant company.
Some take me straight, while some like to savor, my essence to which has been added a flavor.
So put down your cares and sit awhile with me; I'll send you back refreshed and full of energy.
What am I?
A necessity to some, a treasure to many, I'm best enjoyed among pleasant company.
Some take me straight, while some like to savor, my essence to which has been added a flavor.
So put down your cares and sit awhile with me; I'll send you back refreshed and full of energy.
What am I?
Hint: This doesn't need a hint, but in case you peeked: I'll have a grande latte!
Coffee. It was first discovered in the area of Africa now called Ethiopia. Legend has it that a goat herder observed his goats acting unusually frisky after eating berries from a bush. When he tried them himself, his energy was renewed. And the rest is history. Did you answer this riddle correctly?
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The Most Precious Commodity Riddle
What is the most precious commodity?
That which when needed seemingly is never enough,
Yet otherwise can be boringly plentiful.
While waking is oft dreamt of,
Whilst pining can scarcely be thought of.
For beings, is allotted in finite but indefinite quantity.
The more thats given, the more is wasted.
Freedom is akin though this is something more simple,
Not related to virtue or sin.
Unless perhaps, without freedom, or its limit.
What is it?
That which when needed seemingly is never enough,
Yet otherwise can be boringly plentiful.
While waking is oft dreamt of,
Whilst pining can scarcely be thought of.
For beings, is allotted in finite but indefinite quantity.
The more thats given, the more is wasted.
Freedom is akin though this is something more simple,
Not related to virtue or sin.
Unless perhaps, without freedom, or its limit.
What is it?
Hint:
Marrying The Princess Riddle
A king wants his daughter to marry the smartest of 3 extremely intelligent young princes, and so the king's wise men devised an intelligence test.
The princes are gathered into a room and seated, facing one another, and are shown 2 black hats and 3 white hats. They are blindfolded, and 1 hat is placed on each of their heads, with the remaining hats hidden in a different room.
The king tells them that the first prince to deduce the color of his hat without removing it or looking at it will marry his daughter. A wrong guess will mean death. The blindfolds are then removed.
You are one of the princes. You see 2 white hats on the other prince's heads. After some time you realize that the other prince's are unable to deduce the color of their hat, or are unwilling to guess. What color is your hat?
The princes are gathered into a room and seated, facing one another, and are shown 2 black hats and 3 white hats. They are blindfolded, and 1 hat is placed on each of their heads, with the remaining hats hidden in a different room.
The king tells them that the first prince to deduce the color of his hat without removing it or looking at it will marry his daughter. A wrong guess will mean death. The blindfolds are then removed.
You are one of the princes. You see 2 white hats on the other prince's heads. After some time you realize that the other prince's are unable to deduce the color of their hat, or are unwilling to guess. What color is your hat?
Hint: You know that your competitors are very intelligent and want nothing more than to marry the princess. You also know that the king is a man of his word, and he has said that the test is a fair test of intelligence and bravery.
Answer: White.
The king would not select two white hats and one black hat. This would mean two princes would see one black hat and one white hat. You would be at a disadvantage if you were the only prince wearing a black hat.
If you were wearing the black hat, it would not take long for one of the other princes to deduce he was wearing a white hat.
If an intelligent prince saw a white hat and a black hat, he would eventually realize that the king would never select two black hats and one white hat. Any prince seeing two black hats would instantly know he was wearing a white hat. Therefore if a prince can see one black hat, he can work out he is wearing white.
Therefore the only fair test is for all three princes to be wearing white hats. After waiting some time just to be sure, you can safely assert you are wearing a white hat. Did you answer this riddle correctly?
YES NO
The king would not select two white hats and one black hat. This would mean two princes would see one black hat and one white hat. You would be at a disadvantage if you were the only prince wearing a black hat.
If you were wearing the black hat, it would not take long for one of the other princes to deduce he was wearing a white hat.
If an intelligent prince saw a white hat and a black hat, he would eventually realize that the king would never select two black hats and one white hat. Any prince seeing two black hats would instantly know he was wearing a white hat. Therefore if a prince can see one black hat, he can work out he is wearing white.
Therefore the only fair test is for all three princes to be wearing white hats. After waiting some time just to be sure, you can safely assert you are wearing a white hat. Did you answer this riddle correctly?
YES NO
Too Many Photos Riddle
Jack is taking a tour through a museum's American Presidents exhibit. The person leading the tour tells him "We have a picture of each presidency. Currently Barack Obama is the 43rd person to hold the office." But Jack quickly realizes that there are 44 pictures on the wall. But while walking through the exhibit he realizes why this is.
Why is there one too many photos?
Why is there one too many photos?
Hint:
One president served non-consecutive terms (there was a president between his terms) so he held two different presidencies. The president who really did this was Grover Cleveland. Did you answer this riddle correctly?
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How Much Dirt Riddle
Hint:
A Rickety Bridge Riddle
Four people need to cross a rickety bridge at night. Unfortunately, they have only one torch and the bridge is too dangerous to cross without one. The bridge is only strong enough to support two people at a time. Not all people take the same time to cross the bridge. Times for each person: 1 min, 2 mins, 7 mins and 10 mins. What is the shortest time needed for all four of them to cross the bridge?
Hint:
17 mins.
The initial solution most people will think of is to use the fastest person as an usher to guide everyone across. How long would that take? 10 + 1 + 7 + 1 + 2 = 21 mins. Is that it? No. That would make this question too simple even as a warm up question.
Let's brainstorm a little further. To reduce the amount of time, we should find a way for 10 and 7 to go together. If they cross together, then we need one of them to come back to get the others. That would not be ideal. How do we get around that? Maybe we can have 1 waiting on the other side to bring the torch back. Ahaa, we are getting closer. The fastest way to get 1 across and be back is to use 2 to usher 1 across. So let's put all this together.
1 and 2 go cross
2 comes back
7 and 10 go across
1 comes back
1 and 2 go across (done)
Total time = 2 + 2 + 10 + 1 + 2 = 17 mins Did you answer this riddle correctly?
YES NO
The initial solution most people will think of is to use the fastest person as an usher to guide everyone across. How long would that take? 10 + 1 + 7 + 1 + 2 = 21 mins. Is that it? No. That would make this question too simple even as a warm up question.
Let's brainstorm a little further. To reduce the amount of time, we should find a way for 10 and 7 to go together. If they cross together, then we need one of them to come back to get the others. That would not be ideal. How do we get around that? Maybe we can have 1 waiting on the other side to bring the torch back. Ahaa, we are getting closer. The fastest way to get 1 across and be back is to use 2 to usher 1 across. So let's put all this together.
1 and 2 go cross
2 comes back
7 and 10 go across
1 comes back
1 and 2 go across (done)
Total time = 2 + 2 + 10 + 1 + 2 = 17 mins Did you answer this riddle correctly?
YES NO
Something You Might Eat Riddle
Im something you might eat, but I also kill.
I can cause blindness and burns.
Because of me, people lose limbs.
Ive even been known to crash cars.
And yet Im considered beautiful
Small children play with me and parents dont mind.
Some people even live inside of me.
What am I?
I can cause blindness and burns.
Because of me, people lose limbs.
Ive even been known to crash cars.
And yet Im considered beautiful
Small children play with me and parents dont mind.
Some people even live inside of me.
What am I?
Hint:
Center Of Everything Riddle
There is one word that stands the test of time and holds fast to the center of everything. Though everyone will try at least once in their life to move around this word, but in fact, they use it every moment of the day. Young or old, awake or in sleep, human or animal, this word stands fast. It belongs to everyone, to all living things, but no one can master it. The word is?
Hint:
Related Strangers Riddle
A man gets off the bus looking for an address and approaches a couple walking in the same direction for directions. The woman says theyre going that way and take him. Along the way the man asks if theyre related. The woman grins and says, Were not strangers. This mans mother is my mothers mother-in-law. The man is confused but doesnt say anything. When he gets back home he tells his wife about the conversation and she cant figure it out either. They decide to ask their lawyer and he eventually works it out with pen and paper. How are the couple related?
Hint:
The couple is either a man and his daughter or an uncle and his niece. Did you answer this riddle correctly?
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You'll See Me Riddle
Youll see me when the sun is high and also late at night,
Im in the songs of holidays, when the snow is white,
Kings and Queens and royalty, are all found in me,
Im the largest of them all, with just one you see,
Step by step with pounding feet, Im tribes of angry men,
Im above your hands right now, for help or to go again,
Youll use me in the kitchen, or add a little more,
Ill be in the years to come, and the days of yore.
What am I?
Im in the songs of holidays, when the snow is white,
Kings and Queens and royalty, are all found in me,
Im the largest of them all, with just one you see,
Step by step with pounding feet, Im tribes of angry men,
Im above your hands right now, for help or to go again,
Youll use me in the kitchen, or add a little more,
Ill be in the years to come, and the days of yore.
What am I?
Hint:
The Number Twelve (12).
Noon and midnight are both 12 oclock and the Twelve Days of Christmas is a popular Christmas carol.
There are twelve face cards in a standard 52-card deck and twelve is the largest number with one syllable.
There are twelve steps in Alcoholics Anonymous, a troy pound is 12 ounces, there were 12 tribes of Israel and a popular movie was called, Twelve Angry Men (12 members of the jury). There are twelve function keys on your keyboard. F1 often shows a help screen and F5 reloads pages in your browser.
Many recipes measure items by the dozen, adding one more for a bakers dozen. There are twelve months in a year.
Did you answer this riddle correctly?
YES NO
Noon and midnight are both 12 oclock and the Twelve Days of Christmas is a popular Christmas carol.
There are twelve face cards in a standard 52-card deck and twelve is the largest number with one syllable.
There are twelve steps in Alcoholics Anonymous, a troy pound is 12 ounces, there were 12 tribes of Israel and a popular movie was called, Twelve Angry Men (12 members of the jury). There are twelve function keys on your keyboard. F1 often shows a help screen and F5 reloads pages in your browser.
Many recipes measure items by the dozen, adding one more for a bakers dozen. There are twelve months in a year.
Did you answer this riddle correctly?
YES NO
King Octopus Riddle
King Octopus has servants with six, seven, or eight legs. The servants with seven legs always lie, but the servants with either six or eight legs always say the truth.
One day, 4 servants met:
The blue one says: Altogether we have 28 legs;
The green one says: Altogether we have 27 legs;
The yellow one says: Altogether we have 26 legs;
The red one says: Altogether we have 25 legs.
What is the color of the servant that is speaking the truth?
One day, 4 servants met:
The blue one says: Altogether we have 28 legs;
The green one says: Altogether we have 27 legs;
The yellow one says: Altogether we have 26 legs;
The red one says: Altogether we have 25 legs.
What is the color of the servant that is speaking the truth?
Hint:
The green one is telling the truth.
Lets assume that one of them is telling the truth and then try to prove that. Since all four servants are disagreeing then 3 of them must be lying.
The servant telling the truth will have either 6 or 8 legs. The other 3 servants will have 7 legs since they lie. So the total number of legs should be either 27 (6 + 7 + 7 + 7) legs or 29 (8 + 7 + 7 +7) legs. Only green servant could be telling the truth as it said 27 legs.
Alternatively, lets say blue is telling the truth: so the blue one has either 6 or 8 legs. And each of the other octopuses are lying hence have 7 legs each. So our total number of legs: 6 + 7 + 7 + 7 = 27 legs or 8 + 7 + 7 + 7 = 29 legs. But since blue said that altogether they have 28 legs, we know he is lying.
If you follow this same logic for all of them, you realize that only the green octopus can be telling the truth as the number of legs adds up. Did you answer this riddle correctly?
YES NO
Lets assume that one of them is telling the truth and then try to prove that. Since all four servants are disagreeing then 3 of them must be lying.
The servant telling the truth will have either 6 or 8 legs. The other 3 servants will have 7 legs since they lie. So the total number of legs should be either 27 (6 + 7 + 7 + 7) legs or 29 (8 + 7 + 7 +7) legs. Only green servant could be telling the truth as it said 27 legs.
Alternatively, lets say blue is telling the truth: so the blue one has either 6 or 8 legs. And each of the other octopuses are lying hence have 7 legs each. So our total number of legs: 6 + 7 + 7 + 7 = 27 legs or 8 + 7 + 7 + 7 = 29 legs. But since blue said that altogether they have 28 legs, we know he is lying.
If you follow this same logic for all of them, you realize that only the green octopus can be telling the truth as the number of legs adds up. Did you answer this riddle correctly?
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Four Days Of School Riddle
A student has missed an excessive number of days at school and thus the principal called him to his office and requested for an explanation.
The student said, There just isnt enough time for school. I need 8 hours of sleep a day, which adds up to about 122 days a year. Weekends off is 104 days a year. Summer vacation is about 60 days. If I spend about an hour on each meal, thats 3 hours a day or 45 days a year. I need at least 2 hours of exercise and relaxation time each day to stay physically and mentally fit, adding another 30 days.
Add all of that up and you get about 361 days. That only leaves 4 days for school.
The principal is confused, but cant figure out why. What is wrong with the students argument?
The student said, There just isnt enough time for school. I need 8 hours of sleep a day, which adds up to about 122 days a year. Weekends off is 104 days a year. Summer vacation is about 60 days. If I spend about an hour on each meal, thats 3 hours a day or 45 days a year. I need at least 2 hours of exercise and relaxation time each day to stay physically and mentally fit, adding another 30 days.
Add all of that up and you get about 361 days. That only leaves 4 days for school.
The principal is confused, but cant figure out why. What is wrong with the students argument?
Hint:
The student is double counting a lot of the days. A lot of the time spent sleeping, eating, and relaxing occurs during weekends and the summer. Weekends also occur during the summer, so all of these hours are getting counted several times.
And, school is not an all day affair. So the 4 days actually represents more days of school. If school is 6 hours per day, those four days represents 16 days of school. Did you answer this riddle correctly?
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And, school is not an all day affair. So the 4 days actually represents more days of school. If school is 6 hours per day, those four days represents 16 days of school. Did you answer this riddle correctly?
YES NO
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