In Greek mythology, the Sphinx sat outside of Thebes and asked this riddle of all travellers who passed by. If the traveller failed to solve the riddle, then the Sphinx killed him/her. And if the traveller answered the riddle correctly, then the Sphinx would destroy herself. The riddle:

What goes on four legs in the morning, on two legs at noon, and on three legs in the evening?

Oedipus solved the riddle, and the Sphinx destroyed herself.

What breaks yet never falls, and what falls yet never breaks?

What's the next in the series?

H, Be, F, S, Mn, Kr, In, Gd, Tl, ?

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

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?

What is next number in the pattern below:

131 517 192 123 ?

Can you solve this amazing hard number series problem?
7, 8, 10, 12, 16, 18 ?

In a boat, the father of a sailor's son is sitting with the son of the sailor. However, the sailor is not present on the boat.

Can this even be possible?

Name one eight-letter word with 'kst' in the middle, 'in' the beginning, 'and' at the end.?

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

What am I?