What is the fastest way to double your money?

They are three errirs in this question. Can you find them?

What you cannot hold but it is yours?

You board a train. The train will have to enter a tunnel soon. You are claustrophobic. Which place is the best for you to sit?

At a party, there are five people and a whole round cake lying at the centre of the table. Only four people will make a cut and take their piece and the last one will get the remaining piece on the table. How can they make sure that everyone gets a 1/5th of the piece?

Which city is three-fifths chick two third cat and 50% goat?

What goes up but never comes down?

You need to move three matchsticks to form three squares. Can you do it?

What is the last thing you take off before bed?

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.