There are a number of books on a shelf. If one book is the 4th from the left and 6th from the right, how many books are on the shelf?

What Adam and Eve do not have but the rest of the people have?

Cristina leaves home and then she makes exactly 3 left turns and returns home where she found 2 girls wearing the mask.

Who are these two masked girls?

Prove that twice of ten is the same as twice of eleven.

Many have heard it, but nobody has ever seen it, and it will not speak back until spoken to. What is it?

You see me once in June, twice in November, and not at all in May. What am I?

If you drop me I’m sure to crack, but give me a smile and I’ll always smile back. What am I?

There was a strange boy who was born before his father. How can this be possible?

There is an ancient kingdom where every married woman keeps information regarding the fidelity of other men. However, what they don't know is the fidelity of their own husbands. Also, there is an ancient belief that they don't tell each other about the fidelity of their husbands.

On a certain day, the queen of the kingdom declares that she has identified at least one unfaithful man in the kingdom. She allows the wives to identify and gives them authority to kill their husbands if they are unfaithful at midnight.

How will the wives manage it?

Two boys wish to cross a river. The only way to get to the other side is by boat, but that boat can only take one boy at a time. The boat cannot return on its own, there are no ropes or similar tricks, yet both boys manage to cross using the boat.

How?