You want to boil a two-minute egg. If you only have a three-minute timer (hourglass), a four-minute timer and a five-minute timer, how can you boil the egg for only two minutes?

Two friends were betting. One said to the other, "The coin will be flipped twenty times and each time the coin lands on the head, I will give you $2 and each time it lands on the tale, you will give me $3." After flipping the coin twenty times not a single penny was exchanged among them.

How many times did the coin land on heads?

What number divided by 4 is the same as that number minus 4?

Can you arrange four 9's and use at most 2 math symbols, to make the total 100?

John is the son of Jacob.
So,
Jacob is the_____of John's father?

What goes up but never comes down?

What can you hold in your right hand, but never in your left hand?

I have eight fingers and two thumbs but I do not live. What Am I?

Alpha is Beta's sister.

Gamma is a Beta mother.

Delta is Gamma's father.

Tango is Delta's mother.

Then,

How is Alpha related to Delta?

Move four matchsticks to the below square to form three squares?