I make two people out of one. What am I?

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

Sherlock Holmes was challenged to make a pre-drawn line smaller without erasing it. He did it in fractions of seconds. How?

Prove that the below maths equation is true.

8 + 8 = 91

An American nightclub called 'The Coconut Grove' had a terrible fire in which over 400 people died. A simple design flaw in the building led to a high death toll. Subsequently, regulations were changed to ensure that all public buildings throughout the country eliminated this one detail, which proved deadly. What was it?

A seven-year-old kid challenged his classmates that he can make the number one disappear by adding something to it.

How can he do that?

The product of three consecutive numbers is 7980.
Then the sum of these consecutive numbers would be?

A horse was tied to a rope 5 meters long and the horses food was 15 meters away from the horse. How did the horse reach the food?

If an electric train is travelling south, then which way is the smoke going?

I know a 5-digit number having a property that With a 1 after it, it is three times as large as it would be with a one before it.

Guess the number?