what does this picture(rebus) riddle means ?

I never stop running even when I standstill. If I am formed by joining two identical bodies together, can you guess who I am?

How many people must be gathered together in a room, before you can be certain that there is a greater than 50/50 chance that at least two of them have the same birthday?

I have branches, but no fruit, trunk or leaves. What am I?

By removing one matchstick and adding one matchstick, can you convert the word "ZOO" to an animal name?

If one and a half boys, eat one and a half burgers in one and a half hours.

How many burgers can 9 boys eat in 3 hours?

Move three sticks of the spiral below to form a square.

In an office's desk, you find a unique method that shows the current day of the month. Two numbered cubes are used to depict the current date.

Can you find out the numbers on both the cubes so that each date can be mentioned using them?

Please note that you have to use both the cubes to display any date. Thus the 1st day must be represented by 01 and so on.

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?

Can you solve this picture maths equation?