Can you find a seven digit number which describes itself. The first digit is the number of zeros in the number. The second digit is the number of ones in the number, etc. For example, in the number 21200, there are 2 zeros, 1 one, 2 twos, 0 threes and 0 fours.

Alex is stranded on an island covered in forest.
One day, when the wind is blowing from the west, lightning strikes the west end of the island and sets fire to the forest. The fire is very violent, burning everything in its path, and without intervention the fire will burn the whole island, killing the man in the process.

There are cliffs around the island, so he cannot jump off.

How can the Alex survive the fire? (There are no buckets or any other means to put out the fire)

What am I?

What is in seasons, seconds, centuries and minutes but not in decades, years or days?

You may enter, but you may not come in. I have space, but no room. I have keys, but open no lock. What am I?

Can you make numbers like 24, using numbers 3,3,7 & 7 with any arithmetic operator?

Why is a river so rich ?

You have a three-gallon and a five-gallon measuring device. You wish to measure out four gallons.

In which direction should the missing arrow point?

Can you write down eight eights so that they add up to one thousand?