Find The Next Number in the series:

12 13 15 17 111 113 117 119 123 ?

Move three sticks of the spiral below to form a square.

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

I have a five and a three-gallon jar. Assuming there is an infinite supply of water, how can I measure one-gallon water?

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?

This is a famous paradox which has caused a great deal of argument and disbelief from many who cannot accept the correct answer. Four balls are placed in a hat. One is white, one is blue and the other two are red. The bag is shaken and someone draws two balls from the hat. He looks at the two balls and announces that at least one of them is red. What are the chances that the other ball he has drawn out is also red?

Is the statement valid that it does not matter how much older a sibling is, eventually the younger one will be half as old as the older one?

There are 20 people in an empty, square room. Each person has full sight of the entire room and everyone in it without turning his head or body, or moving in any way (other than the eyes). Where can you place an apple so that all but one person can see it?

How many cubic feet of dirt are in a hole of one foot deep, three feet long, and two feet wide?

It spends most of its day eating white, but when it’s quick enough, it gets to eat fruit and sometimes some blue things. It’s in a dark room, where the walls are blue, it runs from a ghost that roams the halls and haunts it all the time. What is it?