Can you place three balls such that the equation shown in the picture holds true?

What happened when the wheel was invented?

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?

Complete the table series riddle by finding the number that can replace "??".

It can't be seen, can't be felt, can't be heard, and can't be smelt.
It lies behind stars and under hills, And empty holes it fills.
It comes first and follows after, Ends life, and kills laughter.
What is it?

I have a hole in my back and legs I lack.
I live where I can’t breathe and I eat without teeth.
What am I?

I know there are two methods by using three time the same number with a plus(+) operator , you can make sum as 60.

One of them is 20+20+20.

whats the other way ?

I know a country, If you remove the last alphabet of its name, it will become a part of your body. Do you name it?

Below the four parts have been reorganised. The four partitions are exactly the same in both arrangements. Why is there a hole?

It's pretty hard to give up.
If you remove a part of it, you will be left with a bit.
Even if you remove another part, the bit still remains.
Remove one more and it still remains.

What is it?