Why do we preferably have round manhole covers and not square ones?

John went to meet his friend Jacob, but when he was about to reach the main gate, John notices that Jacob had a mighty dog who was fastened to the tree. The chain is long enough that it allows the dog to reach the main gate.

How can the John reach the main gate?

Considering the below equation:

V + II - VI = 10
IV - X + VIII = 20
IV - VII + VI = 30

Then, I + II + III = ?

Whats the next number in the below number sequence pattern.

What does it mean?

It is a 5 letter word if you take away first letter it is something you get from sun, if you remove second letter you will get something to eat, if you remove third letter you get a word you use in pointing at and if you remove the fourth letter you get something to drink. What is it?

How many times in a given day, minutes and hour clock comes in a straight line ?

You knock a Table over in the library, and suddenly 20 eyes are looking at you.

What runs around the whole yard without moving?

Place the numbers from 1 to 9 in the circles in a manner that each side of the triangle sums up to 17.