What does the below rebus riddle means?

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?

What does below science rebus mean?

Ag Ag Ag
Ag SPOON Ag
Ag Ag Ag

I am a normal creature, but I have five hands. I can even have more but even then I will be considered normal.

Who am I?

John asked Jack, "The time right now is 7 pm. Can you tell me what will be the time 23, 999, 995 hours later ?"

While Bella does not know the answer, do you ?

The captain of a ship is telling you an interesting story and then poses a question. He says, “I have travelled the oceans far and wide. One time, two of my sailors were standing on opposite sides of the ship. One was looking west and the other one east. And at the same time, they could see each other clearly. Can you tell me how that was possible?”

If you’ve got me, you want to share me; if you share me, you haven’t kept me. What am I?

Replace all '*' with digits 1, 2, 3, 4, 5 and 6 to make below statement true.

* *
x *
=====
* * *

Double it and multiply it by 4. Then divide it by 8 and you’ll have it once more. What number is it?

Manish has to secure 40% marks to pass his B.tech final exams.
He got just 40 marks and failed by 40-marks.

What is the maximum marks?