Tricky riddles

Before Mt. Everest was discovered, what was the highest mountain in the world?

How many letters are there in the English alphabet?

Scientists are trying to find out what is between earth and heaven. Can you find me?

How can a man go eight days without sleep?

If a rooster laid a brown egg and a white egg, what kind of chicks would hatch?

When is a yellow dog most likely to enter a house?

A boat has a ladder that has six rungs, each rung is one foot apart. The bottom rung is one foot from the water. The tide rises at 12 inches every 15 minutes. High tide peaks in one hour. When the tide is at it's highest, how many rungs are under water?

What do you get if you add 2 to 200 four times?

What is the center of Gravity?

There is a boat with a ladder attached to it, the ladder is eight feet tall. If the water rises four feet how much of the ladder will be on top of the water?