Complete the table series riddle by finding the number that can replace "??".

These types of puzzles are known as charades. What you have to do is find two words that are referred to in the first stanza and the second stanza and put them together to form the third word in the third stanza.

Just for example, if my first refers to 'off' and my second refers to 'ice', then my whole will be office.

My first is present - future's past -
A time in which your lot is cast.

My second is my first of space
Defining people's present place.

My whole describes a lack of site -
A place without length, breadth, or height.

What does Alexander the Great and Winnie the Pooh have in common?

The person who makes it has no need for it. He who purchases it does not use it. The person who does use it does not know they are. What is it?

I am a type of vehicle that has two wheels and is powered by humans. What am I?
Hint 1: You can ride me for exercise.
Hint 2: I am environment-friendly.

Replace the question mark with the correct number.

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

John was piloting a plane behind a car but was never able to overtake it. Why?

Twice ten are six of us,

Six are but three of us,

Nine are but four of us;

What can we possibly be?

Would you know more of us?

Twelve are but six of us,

Five are but four, do you see?

What are we?

Can you place six X (crosses) in below board without making three in a row in any way ?