Can you find out the remainder when 3^300 is divided by 5?

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

John’s parents have three sons: Snap, Crackle, and what’s the name of the third son?

A girl has as many brothers as sisters, but each brother has only half as many brothers as sisters. How many brothers and sisters are there in the family?

After a heavy Thanksgiving meal, the night watchman went to work. In the morning, he told his boss he had dreamed that a saboteur planted a bomb in the factory and that he felt it was a warning. The boss promptly fired him. Worker confused, Why boss fire him?

What has many keys but can’t open a single lock?

I add 5 to 9 and get 2. The answer is correct, so what am I?

Can you decipher the below rebus?

PBLUESAISNUERSES

One evening there was a murder in the home of a married couple, their son and daughter. One of these four people murdered one of the others. One of the members of the family witnessed the crime.

The other one helped the murderer.

These are the things we know for sure:

1. The witness and the one who helped the murderer were not of the same sex.

2. The oldest person and the witness were not of the same sex.

3. The youngest person and the victim were not of the same sex.

4. The one who helped the murderer was older than the victim.

5. The father was the oldest member of the family.

6. The murderer was not the youngest member of the family.

Who was the murderer?

I have branches, but no fruit, trunk or leaves. What am I?