How many times can you subtract the number two from the number fifty?

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?

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.

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

I sleep during the day and fly at night, but I have no feathers to aid my flight. What am I?

Why is 6 afraid of 7?

Can you spot the hidden girl in the picture below?

Who are the happiest people in IPL match?

What does the following BrainBat signifies?

ABCDEFGHIJKLMNOPQRSTUVWYZ

QQQQQQQQQQQQQQQQQQQQQQQQQ.

The answer I give is yes, but what I mean is no. What was the question?