Suppose a clock takes 7 seconds to strike 7. How long does it take for the same clock to strike 10?
Riddle AnswerInterview Riddles
Sum of Hats Puzzle
There are 3 people Abel, Bill and Clark. Three of them have numbers (positive integers) written on their hats. They can see the numbers on the other two hats but not their own. The number on one hat is the sum of the numbers on the other two hats. They are given this information and asked in turn if they can identify their number.
In the first round Abel, Bill and Clark each in turn say they don’t know. In the second round Abel is first to go and states his number is 50. What numbers are on Bill and Clark?
Riddle Answer500 Men in an Array
500 men are arranged in an array of 10 rows and 50 columns according to their heights. Tallest among each row of all are asked to come out. And the shortest among them is A. Similarly after resuming them to their original positions, the shortest among each column are asked to come out. And the tallest among them is B.
Now who is taller, A or B?
Riddle AnswerThree Playing Cards
There are three playing cards lying face up, side by side. A five is just to the right of a two. A five is just to the left of a two. A spade is just to the left of a club, and a spade is just to the right of a spade.
What are the three cards?
Riddle AnswerBlind Bartender’s Problem
Four glasses are placed on the corners of a square Lazy Susan (turntable). Some of the glasses are upright (up) and some upside-down (down).
A blindfolded person is seated next to the Lazy Susan and is required to re-arrange the glasses so that they are all up or all down, either arrangement being acceptable.
The glasses may be re-arranged in turns subject to the following rules.
- Any two glasses may be inspected in one turn and after feeling their orientation the person may reverse the orientation of either, neither or both glasses.
- After each turn the Lazy Susan is rotated through a random angle.
- At any point of time if all four glasses are of the same orientation, a bell will ring.
Can you devise an algorithm which allows the blindfolded person to ensure that all glasses have the same orientation (either up or down) in a finite number of turns? The algorithm must not depend on luck.
Riddle Answer