What four weights can be used to balance from 1 to 30 pounds?

How many letters are in the alphabet?

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?

The first person saw the bridge step on it and crossed,
the second person saw the bridge did not step on it but crossed,
the third person did not see the bridge did not step on it but crossed.
Who are these people?

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

A Man gave one of his sons 10 cents and another son was given 15 cents. What time is it?
Hint: Figure out the relation between time and number, is not so easy..:)

Why is 6 afraid of 7?

If you say my name, I will no longer exist. What am I?

The centre of the third figure is empty. What digit should fit inside?

2, 3, 5, 9, 17, _ What is the next number in the sequence?