Spot what is wrong here in below Picture?

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 is the moon similar to a dollar?

I possess a head

I flaunt a tail

But I don't have mouth or legs

Can you find out who I am?

There is something which is always coming but never arrives?

What has a ring but no finger?

There is a straight highway. Four different villages lie on that highway. The distance between them is different. The third village is 60km away from the first village; the fourth is 40 km away from the second; the third is 10 km near to the fourth that it is to the second.

Can you calculate the distance between the fourth and the first village ?

Can you place three balls such that the equation shown in the picture holds true?

Can you identify if it's a murder or a suicide ?

What's the only room from which no one can enter or leave