What four weights can be used to balance from 1 to 30 pounds?

A man has eighty-one cows ( numbered 1,2,3...81 as such). The beauty is that cow no. 1 gives 1ltr of milk, cow no. 2 gives 2ltrs of milk and so on. The man wants to equally distribute the cows among his nine sons so that each one of them gets the same quantity of milk.

How many times do a clock's hands overlap in a day ?

What jumps when it walks and sits when it stands?

Create a number using only the digits 4,4,3,3,2,2,1 and 1. So i can only be eight digits. You have to make sure the ones are separated by one digit, the twos are separated by two digits the threes are separated with three digits and the fours are separated by four digits

Can you divide numbers from 1 to 9 (1 2 3 4 5 6 7 8 9) into two groups so that the sum of the numbers of each group is equal?

Note: 9 cannot be turned over to make it 6.

Can you solve the photo plexer logic ?

What mathematical symbol can be put between 5 and 9, to get a number bigger than 5 and smaller than 9?

How far can you walk into the woods?

I am taken from a mine and shut up in a wooden case, from which I am never released, and yet I am used by almost every person. What am I?