APURV BAJPAI

Think Tank

Here is some exercise for your gray matter :
1. Two spheres are the same size and weight, but one is hollow. They are each made of uniform material, though of course not the same material. With a minimum of apparatus, how can I tell which is hollow?

2. You have two bars of iron. One is magnetized along its length, the other is not. Without using any other instrument (thread, filings, other magnets, etc.), find out which is which?

3. The distance between Cairo and Damascus is 1000 miles. Your mission is to move a 10,000 kilograms load of grass from Cairo to Damascus using your camel, but you have two problems: The camel won't budge unless you let it to continuously chew grass - it consumes 1 kilogram of grass per mile.The camel's maximum load is 1000 kilograms.Can you manage to get ANY of the grass to Damascus?What is the maximum amount of grass that you can get there?

4. Do the 3 hands on a clock ever divide the face of the clock into 3 equal segments, i.e. 120 degrees between each hand?

5. A boy, a girl and a dog are standing together on a long, straight road. Simulataneously, they all start walking in the same direction: The boy at 4 mph, the girl at 3 mph, and the dog trots back and forth between them at 10 mph. Assume all reversals of direction instantaneous. In one hour, where is the dog and in which direction is he facing?

6. Why is a manhole cover round?

7. Fill the following grid with numbers 1,2,3...8 such that no consecutive numbers occupy adjacent squares (Consecutive numbers should not occupy squares which share even a same corner).
```                 ____
|    |
____|____|____
|    |    |    |
|____|____|____|
|    |    |    |
|____|____|____|
|    |
|____|
```

8. A man died and went to Heaven. There were thousands of other people there. They were all naked and all looked as they did at the age of 21. He looked around to see if there was anyone he recognised. He saw a couple and he knew immediately that they were Adam and Eve. How did he know?