Sisters and Brothers

My daughter has as many sisters as she has brothers. Each of her brothers has twice as many sisters as brothers. How many sons and daughters do I have?

Four daughters and three sons. Each daughter has 3 sisters and 3 brothers, and each brother has 2 brothers and 4 sisters.

To figure it out mathematically, you could use the following two equations where G = the number of girls and B = the number of boys:
G – 1 = B
2(B – 1) = G

Solving for G gives you 4 and plugging that in to G – 1 = B gives you a B of 3.

Posted in Brain Teasers

Mixed Animals for $100

At the market you can buy a cow for $10, a pig for $1 and 8 hens for $1. How many animals would you need to buy to get 100 mixed animals for exactly $100?

7 cows, 21 pigs and 72 hens. The trick to this is finding the combination of cows and hens with the same cost and quantity since pigs are already equal. The magic combination is 7 cows and 72 hens, giving you 79 animals that cost $79 ($70 + $9). Then you just add 21 pigs to get to 100 animals.

Posted in Brain Teasers

Thin Barn Word Ladder

Get from the word THIN to BARN by changing one letter at a time and forming another English word in each step.

1. THIN
2. _ _ _ _
3. _ _ _ _
4. _ _ _ _
5. _ _ _ _
6. BARN

1. THIN
2. CHIN
3. COIN
4. CORN
5. BORN
6. BARN

Posted in Brain Teasers

Fourth of July in England

Is there a 4th of July in England?

Yes, there’s a 4th of July in every country. Of course they don’t treat it as a holiday as citizens of the United States do, but that’s not what was asked.

Posted in Brain Teasers

An Elevator Accident

I’m in an elevator with two other people. When it reaches the first floor, one person gets out and six get in. When it reaches the second floor, three people get out and twelve get in. At the third floor, five leave and nine enter. It rises to the fourth floor, one person gets on and the doors close. Suddenly, the elevator cable snaps and the car smashes to the ground. No one survives the fall, yet I’m alive and know exactly how many people go on and off the elevator at every floor. How is this possible?

I got off at the first floor. I’m a security guard and knew how many people got on and off the elevator by watching the surveillance footage.

Posted in Brain Teasers

Alone I’m Unknown

Alone I’m unknown,
With my twin I’m twenty,
And triplets make me a warning.

What am I?

The letter ‘X’. A single x is often used in math as an unknown, along with Mr. X. Two together (XX) make the Roman numeral 20, and three signifies a warning for adult only content, or a warning to other programmers of a problem in source code.

Posted in Riddles
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A Mile Long Train

A mile-long train is moving at sixty miles an hour when it reaches a mile-long tunnel. How long does it take the entire train to pass through the tunnel?

Two minutes. The back of the train would be at the beginning of the tunnel after 1 minute, and would leave the end of the tunnel at the 2 minute mark.

Posted in Brain Teasers

Which Is The Odd Word Out?

Which of the following words is the odd one out?

Chocolate
Biscuit
Lemonade
Jelly
Cake

Lemonade. It’s the only drink in the list.

Posted in Brain Teasers

You Melted My Ice

A full glass of water with a single ice cube sits on a table. When the ice has completely melted, will the level of the water have increased, decreased or remain unchanged?

The water level remains unchanged because the ice cube displaces its own weight. If you’re not convinced, read Archimedes’ Principle, which states that any floating object displaces its own weight of fluid. Still not convinced? Here are a few more sources.

Posted in Brain Teasers

Earthen Home Not a Den

This earthen home is not a den.
I’ve seen impressive rows of them.
As lost as any man becomes,
he always finds his way back home.

A grave.

By Sef Daystrom

Posted in Riddles