Can you replace the question mark with the correct number in the below table sequence?

What is the fastest way to double your money?

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

You need to complete the maze by entering from the entrance marked below in the figure near the yellow circle, bottom left and leaving from the exit point near the green circle, bottom middle.

Rule of Game: You can move only by exchanging green and yellow circles.

1 dollar = 100 cent
= 10 cent x 10 cent
= 1/10 dollar x 1/10 dollar
= 1/100 dollar
= 1 cent

=> 1 dollar = 1 cent

solve this tricky problem?

Joseph buys three kinds of chocolates for 100 rupees. The first one is priced at 5 rupees, second one at 3 rupees and third one at 0.5 rupees.

If he bought 100 chocolates in total, how many pieces do you think he bought each chocolate?

I am weightless, but you can see me. Put me in a bucket, and I'll make it lighter. What am I?

A Child was born in Lahore, Pakistan.

Still child is not a Pakistani citizen.why ?

I am not a bull but I have horns.
I am not an ass but I have a pack saddle.
Wherever I go, I leave silver behind me.

Who am I?

Which is faster, Heat or Cold ? Explain.