## We Go on Vacation

For this puzzle/game, you will need to find a group of friends, preferably 5 or more. The premise is that you will go together on a vacation but each of you can bring only specific items there. The rules regarding which items can be brought and which not are known by one of the players and the other ones are trying to guess them.

In the exchange below, George is the one organizing the trip and the one who knows which items the rest are allowed to bring.

GEORGE: I will take my guitar with me. What do you want to take?

SAM: Can I take an umbrella with me?

GEORGE: No, you cannot take an umbrella, but you can take some sunscreen.

HELLEN: Can I take a scarf with me?

GEORGE: No, you cannot take a scarf, but you can take a hat.

MONICA: Can I take a dress with me?

GEORGE: No, you cannot take a dress, but you can take some makeup.

Can you guess what the rules of the game are?

Everyone is allowed to take with themselves only items whose first letter is the same as the first letter of their names. Thus, George can take a Guitar, Sam can take Sunscreen, Hellen can take a Hat, and Monica can take Makeup.

## Leave No Squares

How many matchsticks do you need to remove so that no squares of any size remain?

Nine matchsticks are enough, as seen from the solution below.

To see that eight matchsticks are not enough, notice that removing an inner matchstick reduces the number of 1×1 squares at most by 2. Since there are 16 such small squares, in order to get rid of them all, we need to remove only inner matchsticks. However, in this case, the large 4×4 square will remain.

## The Least Spoken Language

Which is the least spoken language in the world?

The answer is THE SIGN LANGUAGE.

## Yours but Others Use It

What belongs to you but mostly other people use it?

## The Die Game

You pick a number between 1 and 6 and keep throwing a die until you get it. Does it matter which number you pick for maximizing the total sum of the numbers in the resulting sequence?

In the example below, the picked number is 6 and the total sum of the numbers in the resulting sequence is 35.

No matter what number you pick, the expected value of each throw is the average of the numbers from 1 to 6 which is 3.5. The choice of the number also does not affect the odds for the number of throws until the game ends, which is 6. Therefore, the total sum is always 3.5 × 6 = 21 on average, regardless of the chosen number.

## Symmetry and Perplexion

Find an X > 1, such that:

If we pick X=√2, (using a somewhat ambiguous notation) we get:

To see that the equality above holds, simply note that 2=(√2)² and take √2 root of both sides.

## Peculiar Sequence of Words

What is the peculiar property of this sequence of words?

WHAT, HOLE, ALES, TEST

If you take the first letter from each word, you will spell the first word in the sequence.
If you take the second letter from each word, you will spell the second word in the sequence.
If you take the third letter from each word, you will spell the third word in the sequence.
If you take the fourth letter from each word, you will spell the fourth word in the sequence.

## Breaks and Never Falls

What breaks and never falls, and what falls and never breaks?

Day breaks and night falls.

## Ten Matchsticks

You have these fifteen matchsticks. Remove six of them and leave ten.

Remove 6 matchsticks and leave 9 that spell the word TEN.

## Dead Man in a Hut

One day, the police found a man dead inside a hut. In his left hand, he was holding a gun. In his right hand, he had a recording device. When the recording was played, the police heard the man talking about how horrible his life was and how he wanted it to end. The recording ended with a gunshot. The police was about to call it a suicide until one detective pointed out a very important clue. What was it?

If the man shot himself with the gun, then he would not have been able to stop recording with the device.