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

How many times can you subtract the number two from the number fifty?

Using four sevens (7) and a one (1) create the number 100. Except for the five numerals, you can use the usual mathematical operations (+, -, x, :), root and brackets ()

What runs around the whole yard without moving?

You are trapped in a room with two doors. One leads to certain death and the other leads to freedom. You don't know which is which.
There are two robots guarding the doors. They will let you choose one door but upon doing so you must go through it.
You can, however, ask one robot one question. The problem is one robot always tells the truth, the other always lies and you don't know which is which.
What is the question you ask?

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

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

Our product and our sum always give the same answer. Who are we?

John, a 5-year-old boy, was really fond of the chocolates. He asked his Mother to give him some money to buy his favourite chocolates. His Mother gave him $45. He went to the shopkeeper and asked, "How much is one chocolate for?". The shopkeeper said $3 for one chocolate. Also, if you give me the wrappers of three chocolates, I will give you one for the exchange.
In total, how much chocolate could John eat?

During which month do people sleep the least?