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

Two men are in a desert. They both have packs on. One of the guys is dead. The guy alive has his pack open, and the guy who is dead has his pack closed. What is in the pack?

A word I know,
Six letters contain,
Subtract just one,
And twelve is what remains.

If nine thousand, nine hundred nine dollars is written as $9,909,
how should twelve thousand, twelve hundred twelve dollars be written?

A 3 digit number is such that it's unit digit is equal to the product of the other two digits which are prime. Also, the difference between it's reverse and itself is 396.

What is the sum of the three digits?

John killed hundreds of people mercilessly and yet the police were not able to put her behind the bars. Why?

There are forty elephants and they have forty-fore heads. How can this be possible?

Can you divide numbers from 1 to 9 (1 2 3 4 5 6 7 8 9) into two groups so that the sum of the numbers of each group is equal?

Note: 9 cannot be turned over to make it 6.

There is one thing that goes round the house and also inside the house but never even share a brief touch. What is it?

What goes up but never comes down?