Find The Next Number In The Sequence

30 10 15 13 0 16 -15 ?

What goes through cities and fields, but never moves?

Which wheel of car does not rotate when you turn your car right?

There was a strange boy who was born before his father. How can this be possible?

Take away the whole and some still remain. What is it?

0 0 0 = 6
1 1 1 = 6
2 2 2 = 6
3 3 3 = 6
4 4 4 = 6
5 5 5 = 6
6 6 6 = 6
7 7 7 = 6
8 8 8 = 6
9 9 9 = 6

You can use any mathematical symbols in the space provided to make all above algebraic expressions true.

You walk into a room that contains a match, a kerosene lamp, a candle and a fireplace. What would you light first?

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?

I make two people out of one. What am I?

Today is John's birthday.
A year ago, John had five candles and he lit all the candles except the one at the last.
Now he is going to light all the candles.

How old is John Today?

(He is not five today.....)