Which is faster, Heat or Cold ? Explain.

Which Travels Faster? Solve below famous picture riddle:

What is the fewest number of coins that would be required in order to make sure each and every coin touches exactly three other coins?

Women do it once a year after they turn 19 but men get to do it only once in a lifetime. What is it?

A man calls his dog from the opposite side of a river. The dog crosses the river without a bridge or a boat and manages to not get wet. How is this possible?

Before reading ahead, you must know the fact that only one of the people here is telling the truth.

A says that B is lying.
B says that C is lying.
C says both A and B are lying.

Can you find out who is speaking the truth?

In the addition below, all digits have been replaced by letters. Equal letters represent equal digits and different letters represent different digits.
ABCABA
BBDCAA
ABEABB
ABDBAA
------- +
AAFGBDH
What does the complete addition look like in digits?

How is a fly different from a mosquito?

Which three-digit number, made of consecutive digits, like 567, is 2 less than a cube and 2 more than a square?

There are 2 people near the river and both of them want to get on the other side. The boat can only take one of them. But they got across.
How?