Recreational Mathematics
Teasers
These are really teasers (or riddles if you like) which do not require mathematical treatment.
(1) Re-arrange the 11 letters to form just one word: U S T O O D W E R N J
(2) A man looked at a photograph and said :" Brother and sisters I have none, but this man's father is my father's son." Who's in the photograph?
(3) When the day after tomorrow is yesterday, today will be as far from Sunday as today was from Sunday when the day before yesterday was tomorrow. What day is it?
(4) Complete the series: O T T F F S S _
(5) Complete the series: A E F H I K L M _
(6) What common chemical compound is represented here: H I J K L M N O?
(7) Decrypt this: 3/4 of a cross and a circle complete, 2 semicircles at a perpendicular meet, next add a triangle which stands on 2 feet, 2 semicircles and a circle complete.
(8) You can make a cigarette from 7 cigarette ends. With 49 ends, how many cigarettes can he get?
(9) How many times can you subtract 3 from 24?
(10) If you overtake the second runner in a race, which position are you in?
(11) Put a coin into an empty bottle and insert a cork into the neck of the bottle. How do you retrieve the coin without taking out the cork or breaking the bottle?
(12) A stranger comes to a crosspoint where the signpost has been knocked down, how does he find his way without asking anyone?
(13) A musical instrument can only make 3 notes: a high note, ping; a middle note, mmmmmm; a low note, boing. It is setup according to these rules: If the same note is repeated, it is immediately followed by an mmmmmm; and a note followed by a lower note is followed in turn by a boing. Explain how this instrument when played can get on our nerves.
(14) A, B and C regularly compete in cross-country. After many races, they realize that A has finished before B more often than after him; and B has finished before C more often than after him. Is it possible for C to finished more often before A than after him?
Answers:
(1) JUST ONE WORD
(2) His son
(3) Sunday
(4) E (for Eight)
(5) N. Letters of the alphabet with only straight lines.
(6) Water (H2O)
(7) TOBACCO
(8) 8. Make 7 from the 49, then make the last one from the resulting 7 ends.
(9) Once. The next time you'll be subtracting from 21.
(10) Second.
(11) Push the cork into the bottle, then shake out the coin.
(12) Make the signpost upright and orientate it so that the arm indicating where he came from is pointing the correct direction, then the rest will follow.
(13) If the first 2 notes are mmmmmm-mmmmmm, then it'll settle down and play mmmmmm forever. If the first 2 notes are anything else, then it'll soon settle into this ping-boing-ping-boing...
(14) Yes. Consider just 3 races. The order in the first being A, B, C; the second, B, C, A; the third, C, A, B. Hence A finished 2/3 before B, B 2/3 before C and C 2/3 before A.