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?

Find The Next Number in the series:

12 13 15 17 111 113 117 119 123 ?

Suppose we lay down two cups in front of you. One of the cups is filled with tea and the other one with coffee. Now we ask you to take a spoonful of tea and mix it with the coffee. At this moment, the coffee cup has a mixture of tea and coffee. You have to take that mixture (spoonful) and add it back to the tea.

Can you now tell if the cup of coffee has more tea or the cup of tea has more coffee?

The more of this there is, the less you see. What is it?

Can you arrange four 9's and use at most 2 math symbols, to make the total 100?

Count the number of balls in picture below:

There are 2 sand hourglasses.

The small one can measure 5 hours and the large one can measure 7 hours.

How can we measure 16 hours with 2 sand hourglasses running together ?

Which fur should we be getting from the Lion?

What is next number in the pattern below:

131 517 192 123 ?

Out of four images which one is the odd one out?