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 brings you down but never up?

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.

John drives to his office at 20km/hr. After reaching the office, he realizes that today is a holiday. He went back at an average speed of 30km/hr. Discounting the time spent in the stoppage what was the average speed of his journey?

I have eight fingers and two thumbs but I do not live. What Am I?

A worker is to perform work for you for seven straight days. In return for his work, you will pay him 1/7th of a bar of gold per day. The worker requires a daily payment of 1/7th of the bar of gold. What and where are the fewest number of cuts to the bar of gold that will allow you to pay him 1/7th each day?

O_er_t_o_

Complete the missing letters of the given word.

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

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

When you say goodbye, I am what you need to tie.
I come as a couple and go wherever you run.
Who am I?