I’m tall when I’m young, and I’m short when I’m old. What am I?

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

I never stop running even when I standstill. If I am formed by joining two identical bodies together, can you guess who I am?

How can you make number one disappear by adding something to it?

I cannot talk, but I always reply when spoken to. What am I?

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?

If eleven plus two equals one, what does nine plus five equal?

Four people need to cross a rickety bridge at night. Unfortunately, they have only one torch and the bridge is too dangerous to cross without one. The bridge is only strong enough to support two people at a time. Not all people take the same time to cross the bridge. Times for each person: 1 min, 2 mins, 7 mins and 10 mins. What is the shortest time needed for all four of them to cross the bridge?

I am a type of word that is spelt incorrectly or used differently, on purpose for humour. What am I?
Hint 1: You can find me in a joke.
Hint 2: I am a play on words.

A man dies of old age on his 25 birthday. How is this possible?