There are are five things wrong with this sentence; only geniuses will be able to to spot all of the mitstakes

A brand new Mobile Phone was on sale at 20% as a promotional offer. By what per cent must the Mobile price be increased to sell it at the original price again?

What does the following represent?

N N N N N N N

A A A A A A A

C C C C C C C

How many words can a pen with half refill write?

What number do you get when you multiply all of the numbers on a telephone's number pad?

I make a loud sound when I’m changing. When I do change, I get bigger but weigh less. What am I?

John went to a parrot shop in Mexico, and the parrot owner told him that his parrot is so unique that he repeats everything he hears. John got excited and immediately bought the parrot. John went home and spoke many words, but the parrot does not repeat anything.
He went again to the parrot shop and complaint to the shopkeeper, but the shopkeeper never lied. Explain?

My location can be determined by the below rebus.
So where am i ?

How old is your son? asked a man to his neighbour. My son is five times as old as my daughter and my wife is five times as old as my son. I am twice as old as my wife whereas my grandmother, who is celebrating her eighty-first birthday is as old as all of us put together.

How old is the man's son ?

Can you circle exactly four of these numbers such that the total is twelve?

1 6 1
6 1 6
1 6 1
6 1 6