What has 13 hearts but no other organs?

Can you find out the remainder when 3^300 is divided by 5?

You along with your friend are standing in front of two houses. Each of those houses inhabits a family with two children.

Your friend tells you the below two facts:
1) On your left is a family that has a boy who likes accounts but the other child loves science.
2) On the right is a family with a seven-year-old boy and a newborn baby.

You ask him, "Does either of the family have a girl?"

To this, he replies, "I am not quite sure. But can you guess that? If you are right, I will give you $500."

Which family do you think is likely to have a girl?

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?

I am white when I am dirty, and black when I am clean. What am I?

What part of the chicken has the most feathers?

How much will a 38° angle measure when looked at under a microscope that magnifies ten times?

There is a box in which distinct numbered balls have been kept. You have to pick two balls randomly from the lot.

If someone is offering you a 2 to 1 odds that the numbers will be relatively prime, for example
If the balls you picked had the numbers 6 and 13, you lose $1.
If the balls you picked had the numbers 5 and 25, you win $2.

Will you accept that bet?

I look at you, you look at me, I raise my right, you raise your left. What am I?

Three doctors said that Bill was their brother. Bill says he has no brothers. How many brothers does Bill actually have?