Ten Problems

Would you rather a crocodile attack you or an alligator?

Update: Solutions are posted.

Which English word, other than angry and hungry, ends in -gry?

Update: Solutions are posted.

Abe, Bonnie, Cane and Daria have a two-person boat and can cross the river in 5, 10, 20 and 25 minutes respectively. If a boat containing two people can go only as fast as the slower person, how can all four cross the river in one hour?

Update: Solutions are posted.

There are 6 strings clustered together. One end of each string is at point B (the top), and the other at point A (the bottom). First, two of the ends at point A (randomly) are tied together. Then the two more are tied together, and then the last two. Next, two ends at point B are tied together. Then the two more are tied together, and then the last two.
What is the possibility that all the strings will be tied together in one large loop?

Note: Simplify the answer.

Update: Solutions are posted!

Update: Solutions are posted!

If an electric train is travelling southeast at 50 km per hour, and the wind is lowing southwest at 30 km per hour, which direction is the smoke blowing?

Update: Solutions are posted!

A poor, young knight wants to marry a beautiful princess and she wants to marry him. But the king doesn’t want the marriage. He offers the knight a choice. He can draw one of two slips of paper out of a golden urn. One will say “marriage” and one will say “death”. The princess is able to whisper to the knight that both slips of paper really say “death”. The knight and the princess end up being wed. How does the knight accomplish this?

Well, I’m running out of puzzles to post today, so I’ll just add this classic for the sake of completeness…

If a hunter goes out his front door, goes 50 miles south, then goes 50 miles west, shoots a bear, goes 50 miles north and ends up in front of his house, what color was the bear?

You are told that of 10 bags each containing seemingly indistinguishable 10 gold bars, one bag is counterfeit. If the genuine gold bars weigh 1 kg each and the counterfeit gold bars weigh 0.9 kg each, how can you determine which bag contains the counterfeit gold bars by using a mass scale only once?

Solution

If there are 21 apples on the counter and you take 4 away, how many do you have?

Solution

This one should be easy.

If your drawer contains six pairs of white socks and six pairs of black socks, how many socks, drawn individually and at random, must you draw to ensure you have a matched pair?

Solution

During the Turkish stampede in Thrace, a small detachment found itself confronted by a wide and deep river. However, they discovered a boat in which two children were roawing about. It was so small that it would carry only the two children, or one grown person.

How did the officer get himself and his 357 soldiers across the river and leave the two children finally in joint possession of the boat? And how many times need the boat pass from shore to shore?

Source: 536 Puzzles and Curious Problems by Dudeney (p. 172)

Solution

An old Egyptian Sheik summons his two sons to his death bed. According to tradition, only one of the two sons can inherit his father’s estate.

The two men will have to compete in a very unique camel race. Strangely though, the father will bequeath his fortune to the son whose camel crosses the finish line last.

Undecided as to how to begin the race because they have not solved their father’s riddle, the two brothers seek the advice of a wise man. No sooner have the two sons explained their predicament to the wise man, that they make a hurried dash for the waiting camels. What could the wise man have possibly told the sons for them to have scrambled to start the race?

Update: Solutions have been posted!

Place 8 queens on an 8 by 8 chess board such that no two queens are on the same line.

Update: Solutions have been posted!

There exist three houses that need connection via plumbing to water, gas and electricity. How can the three houses and the three amenities be placed and connected so that no pipe crosses another?

Update: Solutions have been posted!