What has 13 hearts but no other organs?

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

2 ladies and 2 girls need to cross a river in a boat big enough for 1 LADY or 2 girls. How do they do it?

Using four sevens (7) and a one (1) create the number 100. Except for the five numerals, you can use the usual mathematical operations (+, -, x, :), root and brackets ()

It walks on 4 when its young, walks on 2 when it's older, and walks on 3 when its very old?

Imagine a box with two cogwheels, one big with 24 teeth and one small with 8 teeth. The big one is firmly attached to the center of the box which means it does not turn or move while the small one rotates around the big one.

How many times do you think that the smaller wheel will turn compared to the box when it turns once around the big one?

I was born in a small house and I live in it all alone. No windows and no doors have been assigned to my house. The only way I can go out is by breaking through the walls of my house.

Who am I?

When I get multiplied by any number, the sum of the figures in the product is always me. What am I?

What demands an answer, but asks no questions

1 + 9 + 8 = ?
considering, 28 + 8 + 92 = 10