Boxes Of Balls Riddle
The first box has two white balls. The second box has two black balls. The third box has a white and a black ball.
Boxes are labeled but all labels are wrong!
You are allowed to open one box, pick one ball at random, see its color and put it back into the box, without seeing the color of the other ball.
How many such operations are necessary to correctly label the boxes?
Boxes are labeled but all labels are wrong!
You are allowed to open one box, pick one ball at random, see its color and put it back into the box, without seeing the color of the other ball.
How many such operations are necessary to correctly label the boxes?
Hint:
Just One!
Because we know all labels are wrong.
So the BW box must be either BB or WW. Selecting one ball from BW will let you know which.
And the other two boxes can then be worked out logically. Did you answer this riddle correctly?
YES NO
Because we know all labels are wrong.
So the BW box must be either BB or WW. Selecting one ball from BW will let you know which.
And the other two boxes can then be worked out logically. Did you answer this riddle correctly?
YES NO
Eating Burgers Riddle
How many burgers can 9 boys eat in 3 hours ?
Hint:
18
More hours => more burgers.
More boys => more burgers.
The time become twice (3 hours / 1.5 hours).
Boys become six times (9 / 1.5).
Number of burgers = 2 * 6 * Original(1.5)
= 18 Did you answer this riddle correctly?
YES NO
More hours => more burgers.
More boys => more burgers.
The time become twice (3 hours / 1.5 hours).
Boys become six times (9 / 1.5).
Number of burgers = 2 * 6 * Original(1.5)
= 18 Did you answer this riddle correctly?
YES NO
10 Boxes Riddle
There are ten boxes containing some balls. Each of the ball weighs exactly 10 grams. One of those boxes have defective balls (all the defective balls weigh 9 grams each).
An electronic weighing machine is provided to you and you are allowed only one chance of weighing on it.
How will you find out which box has defective balls ?
An electronic weighing machine is provided to you and you are allowed only one chance of weighing on it.
How will you find out which box has defective balls ?
Hint:
Let us simplify boxes by naming them from 1 to 10.
Now the trick here is to pick different number of balls from different boxes. So to simplify things, we will pick balls corresponding to box number.
Thus, pick 1 ball from Box 1, 2 balls from box 2, 3 balls from box 3 and so on. You will have 55 balls altogether. Now, put them all in the balance.
If all balls were weighing accurate 10 grams, the total weight of the 55 balls would have been 550 grams. But one of the box must have had the defective balls.
Suppose if the defective balls were in box number 2, then the total weight will be 2 grams less than 550. If the defective balls were in box 8, the total weight will be less than 8 grams from 550. In this way, you will be able to identify which box has the defective balls. Did you answer this riddle correctly?
YES NO
Now the trick here is to pick different number of balls from different boxes. So to simplify things, we will pick balls corresponding to box number.
Thus, pick 1 ball from Box 1, 2 balls from box 2, 3 balls from box 3 and so on. You will have 55 balls altogether. Now, put them all in the balance.
If all balls were weighing accurate 10 grams, the total weight of the 55 balls would have been 550 grams. But one of the box must have had the defective balls.
Suppose if the defective balls were in box number 2, then the total weight will be 2 grams less than 550. If the defective balls were in box 8, the total weight will be less than 8 grams from 550. In this way, you will be able to identify which box has the defective balls. Did you answer this riddle correctly?
YES NO
The Speed Of A Bee
Two bikes are traveling toward each other at a constant speed of 10 mph. When the bikes are 20 miles apart, a bee flies from the front wheel of one of the bikes toward the other bike at a constant speed of 25 mph. As soon as it reaches the front wheel of the other bike, it immediately turns around and flies at 25 mph toward the first bike. It continues this pattern until the two bikes smush the bee between the two front tires.
How far did the bee travel?
How far did the bee travel?
Hint:
25 miles.
The easiest way to think about this is to consider the time. The bikes will take 1 hour to touch, given that they start 20 miles apart and are each traveling toward each other at 10 mph.
Therefore the bee is buzzing back and forth at 25 mph for 1 hour. Did you answer this riddle correctly?
YES NO
The easiest way to think about this is to consider the time. The bikes will take 1 hour to touch, given that they start 20 miles apart and are each traveling toward each other at 10 mph.
Therefore the bee is buzzing back and forth at 25 mph for 1 hour. Did you answer this riddle correctly?
YES NO
Shoes In The Bed Riddle
Hint:
Branches And Leaves 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
Emptying A Backpack
Hint:
The Homicide Team Riddle
A homicide team enters a crime scene where a dead body of a fat old man lies there on the floor with blood oozing out of his head. The victim is holding a gun and a tape recorder lies there by his side. One of the detective picks up the recorder and plays it "I am tired of this life and hence I have decided to relieve myself from the worldly pains". A gunshot follows the message.
The teams starts investigating a murder investigation.
Why?
The teams starts investigating a murder investigation.
Why?
Hint:
If the man killed himself, he would not have been able to rewind the cassette. Thus it is clear someone else killed him. Did you answer this riddle correctly?
YES NO
YES NO
Filling Your Buckets Riddle
Hint:
Fill the 5 gallon bucket all the way up. Pour it into the 3 gallon bucket until it is full. Empty the 3 gallon bucket. Pour the remaining 2 gallons into the 3 gallon bucket. Fill the 5 gallon bucket all the way up. Finish filling the 3 gallon bucket. Did you answer this riddle correctly?
YES NO
YES NO
The Losing Bet Riddle
Hint:
The Black Child Riddle
Riddle me this
I am the black child of a white father, like a wingless bird flying even to the clouds of heaven. I give birth to tears of mourning in pupils that meet me, even though there is no cause for grief. On my birth I am dissolved into air. What am I?
I am the black child of a white father, like a wingless bird flying even to the clouds of heaven. I give birth to tears of mourning in pupils that meet me, even though there is no cause for grief. On my birth I am dissolved into air. What am I?
Hint:
The Burning Island
You are in the center of on an island that is a kilometer long and half a kilometer wide. The vegetation is very dry from a long drought. Suddenly it catches fire at one end of the island, and a strong wind is blowing it towards you, burning the whole width of the island. There's no beach, only steep cliffs, and the sea is full of sharks. What can you do?
Hint:
Set fire to the other half of the island then walk behind the fire on to the burnt ground Did you answer this riddle correctly?
YES NO
YES NO
Touching Base Riddle
Hint:
Bigger Than You Riddle
Hint:
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