You may enter, but you may not come in. I have space, but no room. I have keys, but open no lock. What am I?

I sleep during the day and fly at night, but I have no feathers to aid my flight. What am I?

A brand new Mobile Phone was on sale at 20% as a promotional offer. By what per cent must the Mobile price be increased to sell it at the original price again?

I can be cracked, made, told, and played. What am I?

You board a train. The train will have to enter a tunnel soon. You are claustrophobic. Which place is the best for you to sit?

All of Jacob's shoes are red except two.
All of Jacob's shoes are green except two.
All of Jacob's shoes are yellow except two.

How many shoes does Jacob have?

It is raining today at 11:59 am. What is the probability of sunny weather after 72 hours?

Baseball bat and ball cost $100. If the bat cost $99 more than the ball, what is the cost of each?

You can hear me, but you can't touch or see me.

What am I?

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?