If two's company, and three's a crowd, then whats four and five ?

Which is the rope you never skip with?

Can you place six X (crosses) in below board without making three in a row in any way ?

In front of you, there are 9 coins. They all look absolutely identical, but one of the coins is fake. However, you know that the fake coin is lighter than the rest, and in front of you is a balance scale. What is the least number of weightings you can use to find the counterfeit coin?

If there are fifteen crows on a fence and the farmer shoots a third of them, how many crows are left?

Three ants are going up a hill, one behind the other. The last ant then says to the other ants, 'There is an ant behind me!'' How come?

What is harder to catch the faster you run?

Complete the table series riddle by finding the number that can replace "??".

If,

6 / 7 = 2
3 / 9 = 7
8 / 2 = 6

Then

4 / 5 = ?

Why do people go to bed?