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

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?

What have one eye but still cannot see?

Take 9 from 6, 10 from 9, 50 from 40, and leave 6.

How Come ??

Do You See It?

We have arranged an array of numbers below. What you have to do is use any kind of mathematical symbol you know excluding any symbol that contains a number like cube root. You can use any amount of symbols but you have to come up with a valid equation for all of them.

0 0 0 = 6
1 1 1 = 6
2 + 2 + 2 = 6
3 3 3 = 6
4 4 4 = 6
5 5 5 = 6
6 6 6 = 6
7 7 7 = 6
8 8 8 = 6
9 9 9 = 6

First, think of the colour of clouds. Next think the colour of snow. Last, think of the colour of the moon. Now, what do cows drink?

What has six faces, but does not wear makeup, has twenty-one eyes, but cannot see? What is it?

Can you identify if it's a murder or a suicide ?

The more it dries, the wetter it becomes. Can you tell what it is?