How can you tell a raw egg from a hard-boiled egg?

Find The Missing Number In the Sequence.
6 25 64 ? 32 1

I am a type of vehicle that has two wheels and is powered by humans. What am I?
Hint 1: You can ride me for exercise.
Hint 2: I am environment-friendly.

Here is what you have to do. You have to throw a ball as hard as you can but it must return back to you even if it does not bounce at anything. Also, you have nothing attached to the ball. There is no one on the other end to catch that ball and throw it back at you.

How will you do it?

What is the largest amount of money that you can possess in change and still if someone asks you for a dollar, you won't be able to give?

Can you solve this amazing hard number series problem?
7, 8, 10, 12, 16, 18 ?

What always comes into a house through the keyhole?

What month of the year has 28 days?

It's a test that will check your IQ.

Suppose you have one 11 minute hourglass and one 13 minute hourglass.

Can you measure exactly fifteen minutes using them ?

While going to your grandmother's house, you counted Twenty houses on the right side. While returning back to your home, you counted Twenty houses on the left side.

How many houses are there between your home and your grandmother's home?