What has no start, end, or centre?

Assume there are approximately 5,000,000,000 (5 billion) people on Earth. What would you estimate to be the result, if you multiply together the number of fingers on every person's left hand? (For the purposes of this exercise, thumbs count as fingers, for five fingers per hand.) If you cannot estimate the number then try to guess how long the number would be.

Can you think of any three-dimensional shape that comprises of exactly two surfaces?

Which is faster, Heat or Cold ? Explain.

Identify the next two numbers in this series.

101, 112, 131, 415, 161, 718, ???, ???

What is next number in the pattern below:

131 517 192 123 ?

There are three light switches outside a room. One of the switches is connected to a light bulb inside the room.
Each of the three switches can be either 'ON' or 'OFF'.

You are allowed to set each switch the way you want it and then enter the room(note: you can enter the room only once)

Your task is to then determine which switch controls the bulb?

Identify the movie name through below Rebus containing Pi Mouse and coconut tree..

I have no life, but I can die. What am I?

Cristina was born in 1888. She just had her 30th birthday today how did that happen?