What occurs twice in a week, once in a year but never in a day?

What is next number in the pattern below:

131 517 192 123 ?

What is in seasons, seconds, centuries and minutes but not in decades, years or days?

A man hijacks an aeroplane transporting both passengers(8 of them) and valuable cargo. After taking the cargo, the man demands nine parachutes, puts one of them on, and jumps, leaving the other eight behind. Why did he want eight?

How is the moon similar to a dollar?

You have a three-gallon and a five-gallon measuring device. You wish to measure out four gallons.

Three ants are going up a hill, one behind the other. The last ant then says to the other ants, 'There is an ant behind me!'' How come?

You find yourself in a strange place guarded by two guards.One of the guard always say truth while other always lies.You don't know the identity of the two.You can ask only one question to go out from there. What should you ask?

What do you think with the below Picture ?

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