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
The German Spy Riddle
A German spy was in Canada trying to steal insider information on how to set up new Maple Syrup factories in Germany. He was being introduced to the operations manager of the biggest factory in Canada.
However the manager was suspicious and decided to test him with a question before he trusted him. So he asked, what would you be sure to find in the middle of Toronto?
The spy thought fast and came up with an answer for the manager.
What did he say?
However the manager was suspicious and decided to test him with a question before he trusted him. So he asked, what would you be sure to find in the middle of Toronto?
The spy thought fast and came up with an answer for the manager.
What did he say?
Hint:
Running Without Winding Riddle
Hint:
Going To New York Riddle
A old man was going to New York. Along the way he met a man with seven wives. Each wife had seven children. Each child had seven cats. Each cat had seven kittens. Kittens, cats, children, wives. How many people are going to New York?
Hint:
Natural Phenomena Riddle
This natural phenomena
Is caused by tectonic plates moving
It happens along a faultline
The Richter Scale measures this thing Body parts remaining: 6
Is caused by tectonic plates moving
It happens along a faultline
The Richter Scale measures this thing Body parts remaining: 6
Hint:
Used By Others Riddle
Hint:
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?
YES NO
YES NO
Five Weeks Old Riddle
Born at the same time as the world, destined to live as long as the world, and yet never five weeks old. What is it?
Hint:
100 Widgets Riddle
If it takes 5 machines 5 minutes to make 5 widgets, how long would it take 100 machines to make 100 widgets?
Hint:
It would take 5 minutes. Each machine takes 5 minutes to make its widget. Therefore, each of the 100 machines would have finished making its widget in 5 minutes. Did you answer this riddle correctly?
YES NO
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
Captured By The Riddler
In the land of Geopolizza, three men were captured by the infamous Riddler. So, the Riddler buries the three men, named 1, 2 and 3 in such a manner, that 1 is in the front, 2 in the middle and 3 in the back. They are buried neck deep, and cannot move, not even their heads. He shows them 5 caps, two of which are red and 3 of them are white. He then switches off the lights and places a hat on top of their heads. The situation is such that no one can see their hat color, 1 is facing the wall and cant say anything, 2 can see 1 and 3 can see both 1 and 2. Then he tells the rules of his game: "If either of you three can tell the correct color of your head, I will let all of you go. However, if any of you answer wrong, all 3 of you will instantly die. Time is 3 minutes."
Upon 2 and half minutes passing, A shouts the answer and all 3 are released free. How did he know the correct answer ?
Upon 2 and half minutes passing, A shouts the answer and all 3 are released free. How did he know the correct answer ?
Hint:
P3 can only be certain of his cap if 1 & 2 are both white. Since he is not certain then 1 & 2 must be either white/red or red/red. 2 knows this but the only combination that he will be able to know the colour of his own cap is if he sees that 1 is wearing a white cap. 1 knows this but as 2 remains uncertain then 1 must be wearing a red cap. Did you answer this riddle correctly?
YES NO
YES NO
A Chinese Man's Name
Hint:
Answering The Question Riddle
Hint:
The 9 Lettered Word
Which is the word in English that has nine letters, and remains a word at each step even when you remove one letter from it, right up to a single letter remaining. List each letter as you remove them, along with the resulting word at each step?
Hint:
'Startling' is the word. Begin by removing 'l', which makes it 'starting', then take away the 't', making it 'staring', and so on - string; sting; sing; sin; in; and, I. Did you answer this riddle correctly?
YES NO
YES NO
Banks On Either Side
This is a long body of water
Which has a bank on either side
Theres a great one in Colorado
For a whitewater rafting ride
What is it?
Which has a bank on either side
Theres a great one in Colorado
For a whitewater rafting ride
What is it?
Hint:
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