What has 13 hearts but no other organs?

If 5 cats catch 5 mice in 5 minutes, how long will it take one cat to catch a mouse?

Can you count the number of matches in the picture below ?

Rectify the following equality 101 - 102 = 1 by moving just one digit.

Can you find the hidden animal in the picture below?

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?

The horse jumps over the king.
Strangely there is absolutely no scratch on him.

Can anyone explain, how is this possible?

In the picture that is attached with this question, you can find a square which comprises of four little squares inside it. Consider this square to be made with matchsticks. You have to remove two matchsticks such that only two squares remain instead of five.How will you do it ?

I am a prime number.
The double of myself is equal to the square of me.

which number am I?

Find The Next Number in this series.
1, 2, 6, 42, 1806 ?