Can you find the missing piece of the Porsche?

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?

Why are all black people so quick ?

John left on a horse on Thursday , was gone for two days, and came back on Thursday after completing his work. How did that happen?

By moving just one matchstick, you need to make the below statement true. Can you do it?

I am a prime number.
The double of myself is equal to the square of me.

which number am I?

I noticed one of the words in the oxford dictionary is spelled incorrectly. What about you?

If we change the South-East direction into North and North-East into West and all others similarly.
Can you find out which direction will be in the place of South-West direction?

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?

What can run but never walks, has a mouth but never talks, has a head but never weeps, has a bed but never sleeps?