The 4 Weight Problem

A merchant had a 40 kg measuring weight that broke into four
pieces as the result of a fall. When the pieces were subsequently
weighed, it was found that the weight of each piece was a whole
number of kilograms and that the four pieces could be used to
weigh every integral weight between 1 and 40 kg. What were the
weight of the pieces.

Note:Weights may be places in either pan of the balance.

101 Hotel Rooms

The Hilton Hotel reserves all its 101 rooms for travelers and each
guest is assigned a room in advance. The first guest arrives but
has forgotten his room number. The hotel clerk, who does not have
access to the reservations book, randomly puts him in one of
the rooms. As the rest of the guests arrive they are given their
reserved room if available or if already taken, are given a random
empty room. What is the chance that the 101st guest gets
her reserved room?

If 7 - 3 = 10124 ...

If
7 - 3 = 10124
6 + 3 = 3279
5 – 2 = 763
11 + 2 = 92613

Then,
15 - 3 =?

Tweleve statements Puzzle

Which of the statements in the box are true?

Ant on a Cube

An ant is placed at one corner of a wire frame in the shape
of a cube. At the diagonally opposite corner is a piece of sugar.
The ant crawls along the all the wires of the frame searching for
the sugar. At each of the 8 corners the ant randomly chooses one of
the 3 wires to follow next (including the one it just traveled)

What is the expected number of edges the Ant will traverse until it
reaches the sugar?

What if the Ant never doubles back on the wire it just crossed?

How many people are there?

How many people must be there if all but 2 are named Smith, all but 2 are named Jones, and all but 2 are named Wilson?

The wine bottle puzzle

I have two 10 litre bottles full of wine and 2 other empty
bottles of 5 and 4 litres. I want to fill 3 litres in each
empty bottles without the help of any additional object and without
pouring out or wasting a single drop of wine.