Which country gets ill every time?

What begins with T, ends with T, and has T in it?

Twenty frogs are sitting on a log floating on the surface of a river. Two of them decide to jump off into the water.

How many frogs are there on the log at this moment?

How is the moon similar to a dollar?

O_er_t_o_

Complete the missing letters of the given word.

I am a white box having no key or lid.
Yet there is a golden treasure inside it.

What Am I?

A man dies of old age on his 25 birthday. How is this possible?

You are presented with three boxes. One of them has a red ball inside and the other two have a black ball inside each of them. You are asked to pick up the one with red ball and you pick one. Now, one of the other boxes is opened and it is found to have a black ball.

You are presented with a chance to change your box with the one that is left closed. Will you change your box? Why or why not?

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.

Place the numbers from 1 to 9 in the circles in a manner that each side of the triangle sums up to 17.