Why is the Hole below a Lock?

Replace the question mark with the number below given a simple math problem.

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

What has many keys but can’t open a single lock?

12345 a famous South Indian actor
567 is a path in jumbled form
8 & 10 are same letters
9 is one among the first six alphabets.
WHO AM I?

What does man love more than life, and hate more than death or mortal strife; that which satisfied men want; the poor have, and the rich require; the miser spends, the spendthrift saves, and all men carry to their graves?

The measurement of time, That can't be found on a clock, But can be looked upon on a map.

Who is He ?

It's a test that will check your IQ.

Suppose you have one 11 minute hourglass and one 13 minute hourglass.

Can you measure exactly fifteen minutes using them ?

What work can one never finish?

Look at this sequence from top to bottom. What is the next number in the sequence?
1
11
21
1211
111221
312211