What is the Five Digit Number?

What 5-digit number satisfies the following requirements?

1. No zeroes
2. First two digits are the same
3. Fourth digit is twice the first
4. Last digit is twice the third
5. Sum of all digits is 18

33264.

There are several ways of solving this. One way is to represent each spot with a letter, A – E.

Then you have these equations:

A = B
D = 2 * A
E = 2 * C
A + B + C + D + E = 18

By simplifying, you get:

4 * A + 3 * C = 18

Plug in values for A and C to find that A = 3 C = 2.

Posted in Brain Teasers

I Build Up Castles

I build up castles.
I tear down mountains.
I make some men blind,
I help others to see.
What am I?

Sand.

Posted in Riddles

Which Switch?

You are standing outside a closed door. On the other side of the door is a room that has three light bulbs in it. The room is completely sealed off from the outside. It has no windows and nothing can get in or out except through the door. On the outside of the room there are three light switches that control each of the respective light bulbs on the other side of the door.

Your assignment is to determine which light switch controls which light bulb. You are allowed to enter the room only once, and once you come out, you must be able to state with 100% certainty which light switch controls which light bulb.

Turn one light switch on, wait a few minutes, then turn it off and turn another light switch on. Go into the room and feel the light bulbs. The one that’s still warm is connected to the switch that you first turned on, the one that is on was the second switch you turned on, and the last bulb is controlled by the switch that you didn’t touch.

Posted in Brain Teasers

Five Games of Checkers

Two children were playing checkers and each played five games. Both children won the same number of games yet there were no ties. How is this possible?

They weren’t playing each other.

Posted in Brain Teasers

A Special-Sized Box

I have a box. The top has an area of 240 square inches, the side 300 square inches and the end 180 square inches. What are the dimensions of the box?

Length = 20
Width = 12
Depth = 15

Posted in Brain Teasers

Counting Squares

How many squares of any size are in this grid?

4 x 4 grid

30.

There are:

16 1×1 squares
9 2×2 squares
4 3×3 squares
1 4×4 square (the whole shape)

Hence, 16 + 9 + 4 + 1 = 30.

Posted in Brain Teasers

No Ears and More Than One Eye

I have no ears, but more than one eye,
Cut me in half, I won’t cry,
Leave me alone and I will die.

What am I?

A potato. The roots growing out of a potato are called eyes, when you cut a potato in half it doesn’t produce any moisture and if you leave a poor potato to its own devices, it will die.

Posted in Riddles

Thanks, You’re Fired

A man is leaving on a business trip and stops by his office on the way to the airport. The night watchman stops him and says, “Sir, don’t take that flight. I had a dream last night that your plane would crash and everyone would die!” The business man cancels his trip and sure enough, the plane crashes, killing all the passengers. The man gives his watchman a $10,000 reward for saving his life, then fires him. Why?

Because his night watchman was sleeping on the job.

Posted in Brain Teasers

Pleased With Their Death

Beulah died in the Appalachians while Craig died at sea. Everyone was much happier with Craig’s death. Why?

Beulah and Craig were hurricanes.

Posted in Brain Teasers

Scrambled Auctioned

What are two other words (anagrams) that can be made from the letters in “auctioned”?

1. Cautioned
2. Education

Posted in Brain Teasers