I look after a bunch of recalcitrant high school kids for a few hours each week. They are generally an affable crew and often I will finish with a logic puzzle to finish a session, which if answered correctly allows them to leave early.

If they thought of it as having to use their brain on top of school work they probably wouldn't have a bar of it but they approach it almost as a form of sport.

Often I will have groups staying well past the time they could go trying to work through to the answer.

The lure of a good logic puzzle seems to be fairly universal.

However since many of the kids are repeat offenders and they are across my kit bag.

My hope is for a contribution or two. Answers from the poster are not required since if the rest of us can't work them out some of my lot might struggle, but I would prefer less of the hanged man with a pool of water at his feet or the dwarf in the lift and more of the logically consistent type.

That being said simple answers to complex questions are always welcome. For instance;

How many grooves are there on a 45rpm record that plays for 30 minutes a side, has an external diameter of 35cm and an internal diameter (where there are no grooves for those who are not familiar with LP records) of 5cm ?

Here is an appetizer;

Three crates of fruit wash up on a desert island which you are marooned on. One is labelled Oranges, another Apples and the third Apples and Oranges. As soon as you lay a finger on the first a Genie appears and says, “Not so fast, before you can eat any fruit you must choose one crate to reach into and without looking remove one piece of fruit. From it you must identify the fruit in all three crates since they are all currently marked incorrectly. You only get one chance.”

What do you do?

Awaiting your favourites if you have any. Thanks.

Do you mean things such as, "How much soil is there is a hole in the ground 2.3m long by 1.7 m wide and 3.2m deep?"

or "A rope ladder with 25 rungs hangs over the side of a ship. Its rungs are 30cms apart with the bottom one just touching the water. The tide is rising at 18cms an hour. How long until 3 rungs are covered by water?"

or are they too simple? But my favorite is:

>>WORLD'S EASIEST QUIZ
(Passing requires 4 correct answers)
Please answer all questions before scrolling down for the answers.

1) How long did the Hundred Years' War last?
2) Which country makes Panama hats?
3) From which animal do we get catgut?
4) In which month do Russians celebrate the October Revolution?
5) What is a camel's hair brush made of?
6) The Canary Islands in the Pacific are named after what animal?
7) What was King George VI's first name?
8) What color is a purple finch?
9) Where are Chinese Gooseberries from?
10)What is the color of the black box in a commercial airplane?

All done?
Remember, you need 4 correct answers to pass.<<

Answers available if required

This is somewhat lame (along the lines of the
hanged man and the pool of water) but here goes anyway.
I'll try to come up with something better next time:

A man is found dead on a little island.
He was alone on the island.
He did not starve or commit suicide.
He wasn't poisoned or killed by a wild animal.
How did he die?

Answer available on request - but I'm sure
you'll work it out. ;-)

Re, apples and oranges, since ALL the boxes are marked incorrectly, you should reach into the "mixed" crate.

If you pick an apple, then the "orange" crate is mixed and the "apple" crate contains oranges.

If you pick an orange, then the "apple" crate is mixed and the "orange" create contains apples.

Lexi, I believe that the man drowned and his body was carried to that island.

The lost dollar?

Three businessmen sit down for lunch in a restaurant advertizing a $10 special, which they all order.

The bill for $30 arrives but they complain and tell the waiter that the meal was not that good and wanted a rebate.

The waiter returns to the cash desk with the $30 and tells the owner about the complaint.

The owner takes five one dollar coins from the till and says OK; give them this discount as a sign of good faith.

The waiter can’t work out how to split $5 between three customers so he sticks $2 in his own pocket.

Back at the table he apologizes and gives each customer $1 back.

So each customer has now handed over $10 and got a $1 rebate. So each paid $9?

3 x $9 = $27, Plus the $2 the waiter pocketed = $29?

Where has the other $1 gone?

"Where has the other $1 gone?"

You should not add the $2, but subtract it:

The owner received: 3 X $9 - $2 = $25