How can you make the following equation true by drawing only one straight line: 5+5+5=550 ?

When it's bad luck to meet a black cat?

You and your two friends are working in a multinational company. How can you three find out the average salary of you all without disclosing your own salary to the other two?

If you remove one from eleven, it becomes ten. If you remove one from nine, it becomes ten.

How is this possible?

Mr Black, Mr Gray, and Mr White are fighting in a truel. They each get a gun and take turns shooting at each other until only one person is left. Mr Black, who hits his shot 1/3 of the time, gets to shoot first. Mr Gray, who hits his shot 2/3 of the time, gets to shoot next, assuming he is still alive. Mr White, who hits his shot all the time, shoots next, assuming he is also alive. The cycle repeats. If you are Mr Black, where should you shoot first for the highest chance of survival?

Solve this riddle by finding the odd one out from the rest.

Find the next number in the series?
2, 12, 36, 80, 150, 252, 392, _ ?

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?

Why is 6 afraid of 7?

How far can you walk into the woods?