What does the below rebus riddle means?

John named his first son Alpha, second Beta, third Charlie and fourth Delta. What is the fifth son's name?

13 decks of cards have been mixed. What is the minimum number of cards that must be taken out from the above-mixed cards to guarantee at least one 'four of a kind?

In the below-given picture of a pretty girl, there is something wrong. Can you find out what it is?

People put me on the table and cut me but do not eat me. What am I?

I am under you when I am whole.
I shift above you if you remove the first letter.
I come all around you if you remove the second as well.

Can you tell me who I am?

In 1990, a person is 15 years old. In 1995, that same person is 10 years old. How can this be?

There are are five things wrong with this sentence; only geniuses will be able to to spot all of the mitstakes

If,

6 / 7 = 2
3 / 9 = 7
8 / 2 = 6

Then

4 / 5 = ?

A patient was diagnosed with some ailment. He was given five different tablets to take at night at an interval of 15 minutes.

How long will it take the patient to consume all the five tablets?