What has six faces, but does not wear makeup, has twenty-one eyes, but cannot see?

In an interview, a boy was asked an unusual question 'How two persons sitting with a table in between them can't see each other?' He was unable to reply. Can you?

What is always in front of you but can’t be seen?

A finger goes in me. You fiddle with me when you're bored. The best man always has me first. What am I?

Many have heard it, but nobody has ever seen it, and it will not speak back until spoken to. What is it?

This is a most unusual paragraph. How quickly can you find out what is so unusual about it? It looks so ordinary, you'd think nothing was wrong with it. Actually, nothing IS wrong with it. But it is not as ordinary as you might think. If you think about it for a bit, you will find out why it is truly so unusual. So what is it? What is so unordinary about this paragraph?

Luis Garavito killed Density x Volume.

Who is Luis Garavito ?

Your mother’s brother’s only brother-in-law is asleep on your couch. Who is asleep on your couch?

Find the mistake in the below maths equations

A = 2
A(A-1) = 2(A-1)
A2-A = 2A-2
A2-2A = A-2
A(A-2) = A-2
A = 1

You have $100 with you and you have to buy 100 balls with it. 100 is the exact figure and you can't go below or above the numbers and you have to use the entire $100. If there is no kind of tax applied how many of each of the following balls will you be able to buy:

Green Balls costing $6
Yellow Balls costing $3
Black Balls costing $0.10

Now, how many of each must you buy to fulfil the condition given?