how puzzling...

Puzzles Updated August 26, 2006

1. Okay, you have two rooms, near each other, but far enough apart that you cannot see anything in one room from the other. One room has 4 light bulbs, let's label them {a b c d}, and the other room has 4 light switches {1 2 3 4} that controls the aforementioned lights. Define a trip as going from the switch room to the light room and back. Start in the switch room, with everything off, and assume that everything is in perfect working condition, can you associate each switch {1 2 3 4} with a light {a b c d} in TWO trips?

Can you do it in ONE trip?

2. Imagine that there is a bridge. Due to weight constraints, only 2 persons can cross the bridge at any one time. Also, since it is pitch black and the bridge is full of holes, you need a flashlight to cross the bridge. Now, there are 4 of you and only ONE flashlight. Additionally, the people in your party can cross the bridge at different speeds. One person can do it in 1 minute, one in 2 minutes, one in 5 minutes, and the last person needs 10 minutes. Can your party of 4 cross the bridge in 17 minutes? No, you cannot carry anybody -- those slow guys are heavy!

3. You have 12 golf balls, let's label them 1 through 12, all of which are indistinguishable by appearance or feel. Eleven of these are indeed exactly the same, however, one weighs slightly different. You are not sure if the rogue ball is heavier or lighter than the rest. Your tool is a balance scale [one of those things that looks like the scales of justice with a pan on each side, you know]. I know that you can probably determine which is the rogue ball in, say 12 uses of the scale. Can you determine which is the rogue ball with 3 uses of the scale? If so, can you also determine if the rogue ball is heavier or lighter than the normal ones?

4. You have 10 boxes, each containing 10 balls. Again, all the balls are indistinguishable by appearance or feel. Nine of the boxes contains balls that each weighs 1 oz. One box contains balls that weighs 0.9 oz. You have a very accurate digital scale [one that measures weight, not a balance one like in Puzzle #3]. Can you determine which box has the light balls in 3 weighings? In 2? In 1?

5. I am your logic teacher. I announce to you that there will be a quiz next week but that the exact day will be a surprise. Being a good logic student, you cheer, saying that logically I cannot give the test at all. Why would you say that? And are you right?

6. I, your logic teacher from #5, and 2 of my students were discussing the problem from #5 when we all dozed off. The students from the Advanced Pranks and Practical Jokes class next doors came in and painted animal faces on us. When we awoke, we all started to laugh at the other two's funny faces. Suddenly, I stopped laughing, why?

7. You land on a game show. The Price is Right no less. Bob Barker shows you three doors, behind one of which is le grande prix, and the other two, worthless consolation prizes. You will keep what's behind the door you pick. After picking door #1, the lovely Janice opens door #2 to reveal a 12-month supply of Rice-a-Roni, the San Francisco treat. Bob then gives you the option of switching your door. Should you switch to door #3? if so, why?

8. You have a standard deck of cards [for those who don't play cards, 52 cards, 4 aces, 4 kings, etc..]. You shuffle the deck thoroughly. You turn over the top card, and keep turning cards until an ace appears. Record the number of cards you have turned over [x]. If you repeat this experiment over time, what is the expected value of x?

9. The following word puzzles do not measure IQ, intelligence, word or math skills. It measures a bit of Americana culture knowledge, and to some extent what I call mental agility. Apparently few people can answer more than 1/2 the puzzles on the first try.

Example: 12 = M. in a Y. Answer: 12 = Months in a Year. Ready?

1 = H. on a U.
1 = W. on a U.
2 = is C., 3's a C.
2 = # it T. to T.
3 = B. M. (S. H. T. R.)
4 = S. and 7 Y. A.
4 = Q. in a G.
4 = H. of the A.
5 = D. in a Z. C.
6 = D. of S.
7 = # of D. S.
7 = B. for 7 B.
7 = W. of the W.
8 = S. on a S. S.
9 = P. in the S. S.
11 = P. on a F. T.
12 = I. in a F.
12 = S. of the Z.
12 = D. of C.
13 = S. on the A. F.
13 = D. in a B. D.
14 = D. in a F.
18 = H. on a G. C.
24 = H. in a D.
26 = L. of the A.
29 = D. in F in a L. Y.
32 = D. F. at which W. F.
40 = D. & N. of the G. F.
50 = S. on the A. F.
50 = W. to L. Y. L.
54 = C. in a D. (With the J.)
57 = H. V.
64 = S. on a C. B.
76 = T. in the B. P.
80 = D. to G. A. the W.
88 = P. K.
90 = D. in a R. A.
92 = the A. N. of U.
99 = B. of B. on a W.
101 = D.
200 = D. For P. G. in M.
1,000 = W. that a P. is W.
1,000 = # of S. L. by the F. of H. of T.
1,001 = A. N.
20,000 = L. U. the S.

10. Miscellaneous... these are not math or logic puzzles in the strict sense, more like "pay-attention" puzzles.

a. A child is born in Boston, Massachusetts to parents who were both born in Boston, Massachusetts. The child is not a United States citizen. How is this possible?
b. Before Mount Everest was discovered, what was the highest mountain on Earth?
c. Clara Clatter was born on December 27th, yet her birthday is always in the summer. How is this possible?
d. Captain Frank and some of the boys were exchanging old war stories. Art Bragg offered one about how his grandfather led a battalion against a German division during World War I. Through brilliant maneuvers, he defeated them and captured valuable territory. After the battle he was presented with a sword bearing the inscription: "To Captain Bragg for Bravery, Daring and Leadership. World War I. From the Men of Battalion 8." Captain Frank looked at Art and said, "You really don't expect anyone to believe that ridiculous yarn, do you?" What's wrong with the story?
e. In what year did Christmas and New Year's fall in the same year?
f. A woman from New York married ten different men from that city, yet she did not break any laws. None of these men died and she never divorced. How was this possible?
g. Why are 1990 American dollar bills worth more than 1989 American dollar bills?
h. How many times can you subtract the number 5 from 25?
i. A taxi driver was called to take a group of passengers to the train station. The station is normally an hour away, but with traffic being extra heavy, it took a full hour and a half. On the return trip the traffic was still as heavy and yet it took only 90 minutes. Why?
j. How could you rearrange the letters in the words "new door" to make one word? Note: There is only one correct answer.
k. Even if they were starving, natives living in the Arctic would probably never eat a penguin's egg. Why not?
l. Which is correct to say, "The yolk of the egg are white" or "The yolk of the egg is white"?
m. There were an electrician and a plumber waiting in line for admission to the "International Home Show". One of them was the father of the other's son. How could this be possible?
n. After the new Canon Law that took effect on November 27, 1983, would a Roman Catholic man be allowed to marry his widow's sister?

11. You stand at the edge of a desert which is 1,000 miles wide at the shortest possible route. You have a cargo of 3,000 bananas. Your beast of burden is a camel who needs to eat 1 banana every mile he travels. He also can only carry a maximum of 1,000 bananas at a time. How many bananas can you deliver to the other side of the desert? a. you don't need water, b. you cannot carry anything, c. there are nothing else that you have access to in the desert. There is no trick -- everything is stated in the problem. [credit - gene kim]

12. Similar to the above. You are an explorer trying to cross a desolate desert. The journey will take 6 days. However, you can only carry provisions for 4 days. The local tribe can provide bearers to assist you. They are unionized however, and cost $500 per man per day or any part thereof. Provisions are cheap -- consider provisions to be free. What's the least number of bearers needed and what is the most cost effective plan to cross the desert? No, you cannot plan to kill your bearers.

13. Mr Smith has two children, at least one is a boy. Mr Jones has two children, the eldest is a boy. Is the probability that Mr Smith has 2 boys the same as Mr Jones's?

14. Joe lives in Studsville. Due east of Studsville is Blondesville and due west of Studsville is Brunettesville. There is a train that runs from Brunettesville to Blondesville which stops regularly once every hour at Studsville. There is also a train that runs the other way, also stops regularly once an hour. Joe has two girlfriends, one blonde [Jill] and one brunette [Joan]. He likes them equally so he makes it a rule to go to the station and take the first train that stops there, whether it be the eastbound Blondesville train or the westbound Brunettesville train. After a few months, he noticed that he visits Jill much more than his Joan. Yes, it would seem that blondes do have more fun. Quantitatively, he visits Jill about 5 times more often than Joan. The trains have the same frequency and his arrival at the station is totally random. Why the difference?

15. Say that you have a glass of pure water, and a glass of an equal volume of blue dye. If you take a teaspoon of the dye and put it in the water, then take a teaspoon of the dye water mixture and put it in the dye, which glass will have the greater concentration of the original liquid. That is, is the water more diluted than the dye or vice versa?

16. My mom went to a flea market and saw plates for $5, spoons for $1, and little paper umbrellas for 5 cents. She spent $100 for 100 items and yes, she bought all three kinds of items. What did she buy?

17. There are 2 pieces of string. Each piece is made of a different material and are of different lengths. Both pieces of string takes exactly 1 hour to burn from 1 end to the other end. The speed of burning is not uniform throughout, so it can burn quickly first than slowly at the end or any random way. If you are given only these 2 pieces of string and a box of matches, how do you measure 45 minutes? The solution only requires you to burn the strings. No other actions like cutting, measuring, etc is involved. [credit malcolm thompson]

18. Below is a quiz written [supposedly] by Einstein. Supposedly, 98% of the people in the world cannot solve the quiz -- either cannot, or haven't yet been to my page :). Are you among the other 2%? Here you go...

Facts:

There are 5 houses in 5 different colours
In each house lives a person with a different nationality.
These 5 owners drink a certain beverage, smoke a certain brand of cigar and keep a certain pet.
No owners have the same pet, smoke the same brand of cigar or drink the same drink.

Hints:

The Brit lives in a red house.
The Swede keeps dogs as pets.
The Dane drinks tea.
The green house is on the left of the white house.
The green house owner drinks coffee.
The person who smokes Pall Mall rears birds.
The owner of the yellow house smokes Dunhill.
The man living in the house right in the centre drinks milk.
The Norwegian lives in the first house.
The man who smokes Blend lives next to the one who keeps cats.
The man who keeps horses lives next to the man who smokes Dunhill.
The owner who smokes Blue Master drinks beer.
The German smokes Prince.
The Norwegian lives next to the blue house.
The man who smokes Blend has a neighbour who drinks water.

The question is... WHO KEEPS THE FISH?

19. Shackleford, Campbell, Garfield, and Colson make up a flight crew -- pilot, copilot, navigator, and engineer, but not necessarily in that order. Using the clues below, find out who holds which job. The clues may or may not be of any use to you.

The pilot and copliot are good friends.
Shackleford and Colson are not good friends.
The engineer's wife is aboard the plane as a passenger.
Shackleford and Colson do not wear glasses...
...but I am not sure about the other two guys.
Only Garfield and Colson are married.
Garfield had lunch with the copilot.
The pilot doesn't wear glasses...
...but the navigator does
The navigator is engaged to the stewardess.
The stewardess is extremely good-looking.

20. These are classic IQ type questions from the 11/99 issue of Esquire Magazine. See problem (1) on that link [the visually oriented ones I shall omit here].

visual problem
Street is to curb as river is to ____.
a. bank b. bed c. dam d. ocean e. stream
Size is to grow as knowledge is to ____.
a. believe b. decide c. know d. learn e. persuade
Canyon is to bridge as mountain is to ____.
a. cave b. mine c. peak d. ridge e. tunnel
Water droplet is to air bubble as island is to ____.
a. bay b. continent c. crater d. lake e. peninsula
Mountain is to pyramid as river is to ____.
a. bathtub b. canal c. fountain d. reservoir e. well
Water is to stalactite as wind is to ____.
a. dune b. geyser c. skyscrapper d. stalagmite e. volcano
What number best completes the sequence?
1000, 1002, 1006, 1012, 1020, ____.
What number best completes the sequence?
13, 57, 911, 1315, 1719, ____.
One (infinite) line can divide an (infinite) plane into two regions. Two distinct line can divide a plane into 3 or 4 distinct regions. How many regions can 3 distinct lines divide a plane into?
The cities Weston and Easton are connected by parallel eastbound and westbound railroad tracks. Trains run daily on a 24-hr basis. Trains depart Weston for Easton every hour on the hour (i.e., at 6.00, 7.00, etc). Trains depart Easton for Weston on the half hour (i.e., 6.30, 7.30, etc). In either direction, the trip takes 6 hours. If you take a train from Weston to Easton, how many trains do you pass on the way?
If bond equals 1.10.3.2 and market equals 7.6.8.1.5.9, then bank equals _____.
What does 1000 - 999 + 998 - 997 +... + 4 - 3 +2 -1 =?
A couple plans to have three children. If the odds of having a girl is exactly the same as the odds of having a boy (1 in 2), then what are the odds of have all three children of the same sex?

21. Here is a classic riddle, courtesy of ay, domo!

In ancient Greece, when the Gods ruled the world, Iganor, the God of bad luck, sentenced a mortal warrior to death. Iganor was a reasonable God and allowed the warrior to choose his method of death. The warrior was allowed to make one statement; if the statement were true, the warrior would be fed to the dragons and if the statement were false, the warrior was to be killed by a poisoned fruit tart!

The warrior mulled his predicament over and finally made a statement. After hearing it, Iganor had no choice but to free the warrior. What did the warrior say to save himself?

22. Here is a straight up math problem, courtesy of tj, domo!

A boat leaves a pier and travels UPSTREAM [ie, against the river current] for one mile. There, it passes a log floating on the river heading [obviously] downstream. The boat then keeps traveling for one hour; then turns around and heads back toward the pier where it came from. The boat and the log arrive at the pier simultaneously. Assume that the boat is traveling at a constant engine speed, and that the river is also flowing at a constant speed.

How fast is the boat going? What about the river?

23. Here's a good planning puzzle. Click on the blue circle to start. http://freeweb.siol.net/danej/riverIQGame.swf or http://www.onlinegameshub.com/pages/river-iq-game.html The object is to get everyone across the river. The rules are: The Mom cannot be with any of the boys if the Dad is not present. The Dad cannot be with any of the girls if the Mom is not present. The thief (striped shirt) cannot be with anyone unless the Cop is present. Only the Cop, Mom, and Dad can operate the raft, and only 2 people can be on the raft at any one time.

Email solutions or pleas of help, page 1 or help, page 2 to me at the address below. Want more puzzles? Check out the Puzzles Web Ring below, of which I am a proud member. Or try riddlesandmore, mensa, IQ Tests, or densa.

Koans are not traditional puzzles either, but they do exercise your brain. Try these sites for a feel of them. If you wish to discuss them, feel free to email me. Shanti's Koan of the Month. Ken Boucher's NoZen Page. k-Zone's Koan of the Day.

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