Why is the Hole below a Lock?

A 3 digit number is such that it's unit digit is equal to the product of the other two digits which are prime. Also, the difference between it's reverse and itself is 396.

What is the sum of the three digits?

You walk into a room that contains a match, a kerosene lamp, a candle and a fireplace. What would you light first?

Can you convert the number zero(0) into a positive number using just one mathematical operator ?

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?

In the four images below, can you find the odd one out?

This puzzle is for Harry Potter fans. Do you know why Tom Riddle is called Lord Voldemort?

Replace the question mark in the picture below.

A time long back, there lived a king who ruled the great kingdom of Trojan House. As a part of the renovation of the kingdom to meet future security needs, he asked his chief architect to lay down a new play in a manner that all of his 10 castles are connected through five straight walls and each wall must connect four castles together. He also asked the architect that at least one of his castles should be protected with walls. The architect could not come up with any solution that served all of King's choices, but he suggested the best plan that you can see in the picture below. Can you find a better solution to serve the king's demand?

Can you find the missing letter in the sequence?
S - T - I - L - ? - T - F - Y - C