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?

If I remove one from eleven it becomes Ten and if I remove one from nine also becomes Ten. How?

Solve the puzzle by telling what does below picture means.

Is the statement valid that it does not matter how much older a sibling is, eventually the younger one will be half as old as the older one?

There are 2 people near the river and both of them want to get on the other side. The boat can only take one of them. But they got across.
How?

Its something that each of us devours,
Not just us but birds, beats, trees, and flowers,
Frets iron and nibbles steel,
Toil hard stones to meal,
Exterminates king, collapse town,
And blows the mountains down.

Quickly Solve this riddle

7 - 4 + 3 * 0 + 1 = ?

Something Extraordinary happened on May 6th 19778 at 12:34am what was that?

If you go to the movies and you're paying, is it cheaper to take one friend to the movies twice, or two friends to the movies at the same time?

What number does the below three word/phrase identify and why?
1. Deck
2. Year
3. Singing in the Rain