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

We have four gears with below features=> Both Gear A and D has 60 teeth=> Gear B has 40 teeth=> Gear C has 20 teeth=> Every two minutes, Gear B makes 25 full turns.What is the relative speed of Gear A and Gear B?

If there are fifteen crows on a fence and the farmer shoots a third of them, how many crows are left?

It is always ahead of me yet I can never see it. What is it?

Luis Garavito killed Density x Volume.

Who is Luis Garavito ?

What number when divided in half becomes zero?

If,
29 - 1 = 30
9 - 1 = 10
14 - 1 = 15

Based on similar logic, Can you prove that the below algebraic equation is true?
11 - 1 = 10 ?

A plane crashed between the border of Mexico and America. Where do you bury the survivors?

Joseph buys three kinds of chocolates for 100 rupees. The first one is priced at 5 rupees, second one at 3 rupees and third one at 0.5 rupees.

If he bought 100 chocolates in total, how many pieces do you think he bought each chocolate?

They came out at night, without being called.
They lost at day, without being stolen.
Who are they?