What happened when the wheel was invented?

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.

Check out the number list below and find what number comes next in the sequence.

111 , 113 , 117 , 119 , 123 , 137 , ?

Three people are in a room. Ronni looks at the Nile. The Nile looks at Senthil. Ronni is married but Senthil is not married. At any point, is a married person looking at an unmarried person? Yes, No or Cannot be determined.

I know a nine-letter word having only one vowel.
Do you ?

What you cannot hold but it is yours?

I have Rs.50 and I spend it in the way as below.

My friends called me Iron59 because my parents are a chemist and a mathematician. What is my real name?

A man calls his dog from the opposite side of a river. The dog crosses the river without a bridge or a boat and manages to not get wet. How is this possible?

If I remove one from eleven it becomes Ten and if I remove one from nine also becomes Ten. How?