A Perfect Counterfeit

A man can make perfect counterfeit bills. They look exactly like real ones, they’re made of exactly the same materials, made the same way, everything. So perfect, one could pretty much call them real bills. One day he successfully makes a perfect copy of another bill. However, he gets caught when he tries to use the copy. How is this possible?

As a counterfeiter, he had lots of counterfeit bills around and he accidentally used one of them as his original. So he made a perfect copy of a counterfeit bill.

Posted in Brain Teasers

No New Digits

A six-digit number represented by ABCDEF (each letter represents a different number) can be multiplied by 2, 3, 4, 5, and 6 and yet no new digits appear in the result. As a matter of fact, all the digits are rotated. What is the number?

142857 (The first 6 digits of 1/7)

2 x 142857 = 285714
3 x 142857 = 428571
4 x 142857 = 571428
5 x 142857 = 714285
6 x 142857 = 857142

Posted in Brain Teasers

A Fox, Chicken and Sack of Grain

You have a fox, a chicken and a sack of grain. You must cross a river with only one of them at a time. If you leave the fox with the chicken he will eat it; if you leave the chicken with the grain he will eat it. How can you get all three across safely?

Fox and (little) chicken

Take the chicken over first. Go back and bring the grain next, but instead of leaving the chicken with the grain, come back with the chicken. Leave the chicken on the first side and take the fox with you. Leave it on the other side with the grain. Finally, go back over and get the chicken and bring it over.

Posted in Brain Teasers

The Mystery Six-Digit Number

Find a six-digit number containing no zeros and no repeated digits that satisfies the following conditions:

1. The first and fourth digits sum to the last digit, as do the third and fifth digits.
2. The first and second digits when read as a two-digit number equal one quarter the fourth and fifth digits.
3. The last digit is four times the third digit.

192768.

If you call the number ABCDEF, then you get the following equations.

1. A + D = F and C + E = F
2. AB = DE / 4
3. F = 4 × C

The only numbers that work for C and E are 2 and 6 or 4 and 8, and in order to make F a single-digit number, we can deduce that C = 2, E = 6 and F = 8.

So far, our number is AB2D68.

We know A + D = 8 so A and D are both odd numbers. The only odd number less than 8 that we can use for D to make one-quarter of two-digit number D6 also be a two-digit number is 7, so D = 7 and A is 1. This makes the two-digit number AB 19.

Posted in Brain Teasers

Subtract One and Twelve Remains

A word I know, six letters it contains, subtract just one and twelve remains.

Dozens, dozen.

Posted in Riddles

Tree That’s Difficult To Get Along With

Which tree is the most difficult to get along with?

A crab tree.

Posted in Riddles

Short Black Dress

In the day I stand tall in a white petticoat. By evening I’m in my short black dress. What am I?

The wick of a candle.

Posted in Riddles

2 + 2 = 5

What is the similarity between “2 + 2 = 5” and your left hand?

Neither is right. Two plus two equals five isn’t right, or correct and your left hand is not your right hand.

Posted in Brain Teasers

Kings And Lords And Christians Raised Them

Kings and lords and christians raised them
Since they stand for higher powers
Yet few of them would stand, I’m certain,
If women ruled this world of ours.

A tower.

Posted in Riddles

What Do You Serve?

What do you serve that a polite recipient would immediately send back?

A ball, when you’re playing tennis, volleyball, table tennis, etc.

Posted in Riddles