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December 16, 2012

Gold Coin Barrels

There are 10 barrels of gold coins. In that, some of the barrels contain 1 gram gold coins and some of the barrels contain 2 gram gold coins. There is a weighing machine which is allowed to weigh only once. Which of the barrels contain 2 gram coins?

October 28, 2012

Opaque Cube Puzzle

You are making an opaque cube (ie you cannot see through its sides). It can be any size that you want it to be. Where do you place the cube so that you can see as many sides as possible?

September 20, 2012

Box Packing Puzzle

Three boxes are all labeled incorrectly, and you must get the labels right. The labels on the boxes read as given below.

To gain the information you need to move the labels to the correct boxes, you may remove a single item from one of the boxes. You may not look into the boxes, nor pick them up and shake them, etc.

Can this be done? If so, how? If not, why not?

July 22, 2012

Murder in the Desert

This is a story about three people (A, B and C) crossing a desert. A hated C and decided to kill him - he poisoned the water in his sack (only C had water). B also wanted to kill C (not knowing that the water of C had been already poisoned) and so B made a hole into the sack of C and the water spilt out. A few days later C died of thirst.
Who was the murderer - A or B?

May 13, 2012

The Trainee Technician

A 120 wire cable has been laid firmly underground between two telephone exchanges located 10km apart. Unfortunately after the cable was laid it was discovered that the individual wires are not labeled. There is no visual way of knowing which wire is which and thus connections at either end is not immediately possible.

You are a trainee technician and your boss has asked you to identify and label the wires at both ends without ripping it all up. You have no transport and only a battery and light bulb to test continuity. You do have tape and pen for labeling the wires. What is the shortest distance in kilometers you will need to walk to correctly identify and label each wire?

April 28, 2012

Philosopher's Clock

One absentminded ancient philosopher forgot to wind up his only clock in the house. He had no radio, TV, telephone, internet, or any other means for telling time. So he traveled on foot to his friend’s place few miles down the straight desert road. He stayed at his friend’s house for the night and when he came back home, he knew how to set his clock. How did he know?

March 17, 2012

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.

January 7, 2012

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?

January 1, 2012

If 7 - 3 = 10124 ...

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

15 - 3 =?