Suppose a clock takes 7 seconds to strike 7. How long does it take for the same clock to strike 10?
Riddle AnswerMath Riddles
Old Auto
An old auto is to drive a stretch of 2 miles, up and down a hill. Because the auto is so old, you cannot drive the first mile (the ascent) faster than 15 miles per hour.
How fast do you have to drive the second mile (going down the hill) in order to get an average speed of 30 miles per hour?
Riddle AnswerBrothers Jack and John
The combined age of Jack and John is 49. Jack is twice as old, as John was when Jack was as old as John is now. How old are the brothers?
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 Answer7 Daughters
A woman has 7 daughters and each of them has a brother. How many children does the woman have all together?
Riddle Answer