#1 - Ping Pong Problem

Your last good ping-pong ball fell down into a narrow metal pipe imbedded in concrete one foot deep.
How can you get it out undamaged, if all the tools you have are your tennis paddle, your shoe-laces, and your plastic water bottle, which does not fit into the pipe?

View Answer Discuss

All you have to do is pour some water into the pipe so that the ball swims up on the surface.

Edit:
oysterboy22's wording solution: none of those random things are going to help you, but the whole point is the person thinks they have to use the tools, while what they really have to do is urinate in the hole.

#2 - Dish Full Problem

A Petri dish hosts a healthy colony of bacteria. Once a minute every bacterium divides into two. The colony was founded by a single cell at noon. At exactly 12:43 (43 minutes later) the Petri dish was half full.
At what time will the dish be full???

View Answer Discuss

The dish will be full at 12:44.

Answer for old wording:
The saucer was half full at 11.59 - the next minute there will be twice as many of them there (so full at 12.00).

#3 - Escape from Killing Problem

A man aproaches you in a dark alley. He says, 'If you tell a lie, I will kill you with a knife. If you tell the truth, I will kill you with a gun.'
What do you say to stay alive?

View Answer Discuss

Recognize that only declarative statements have a truth value.
Don't make a declarative statement; that way it won't be the truth or a lie.
Here are three possibilities:

[1] Remain silent. - or if you must say something, ask a question
[2] Why do you want to kill me? - or exclaim something:
[3] No! Please do not kill me!

#4 - Length Of Pole Problem

There is a pole in a lake. One half of the pole is in the ground, another one third is covered by water and eight feet is out of the water. What is the total length of the pole in feet?

View Answer Discuss

48 feet

lets say x is the total height of the pole...
x/2 + x/3 + 8 = x
(3x+2x+48)/6 = x
5x+48 = 6x
x = 48

#5 - Dollar Problem

If nine thousand, nine hundred nine dollars is written as $9,909,
how should twelve thousand, twelve hundred twelve dollars be written?

View Answer Discuss

$13,212

#6 - Brick Problem

How many bricks does it take to complete a building that is 20 feet wide, 35 feet deep, and 14 feet tall made of brick?

View Answer Discuss

One [the last one, which completes it].

#7 - Sum Problem

A lily pad doubles in size every day. If on the 60th day the pond is exactly filled with the lily pad, on what day is the pond exactly half covered?

View Answer Discuss

Day 59. Since it doubles in size each day, the day before it exactly covers the pond it will half cover it.

#8 - Brainbat Represent

1. What does:
TIM JOB
represent?

2. What does:
MO_ _
represent?

View Answer Discuss

1. Part Time Job.
2. Half Moon.

#9 - Next Child Name Problem

A pregnant woman is preparing to name her seventh child. Her children's names so far are Dominique, Regis, Michelle, Fawn, Sophie and Lara. What will she name her next child -- Jessica, Katie, Abby or Tilly?

View Answer Discuss

Tilly. She is following the scale-- Do, Re, Mi, Fa, So, La...Ti.

#10 - Egg Problem

A man is walking down a road with a basket of eggs. As he
is walking he meets someone who buys one-half of his eggs
plus one-half of an egg.
He walks a little further and meets another person who buys
one-half of his eggs plus one-half of an egg.
After proceeding further he meets another person who buys
one-half of his eggs plus one half an egg. At this point he
has sold all of his eggs, and he never broke an egg.
How many eggs did the man have to start with?

View Answer Discuss

Seven Solution; Person one buys half the eggs [3 1/2] plus 1/2 an egg, or 4 total. No eggs broken. This leaves 3 eggs. Person 2 buys half the remaining eggs [1 1/2] plus 1/2 an egg, or 2 total. Again no eggs broken. This leaves 1 egg. Person 3 comes along, and he buys half the eggs [1/2] plus 1/2 an egg, or 1 egg. No broken eggs, eggs all sold