Can you arrange four 9's and use at most 2 math symbols, to make the total 100?

What is the fastest way to double your money?

I am a three digit number.
My tens digit is five more than my ones digit.
My hundreds digit is eight less than my tens digit.
What number am I?

How can you write nineteen in a manner that if we take out one, it becomes twenty?

You measure my life in hours
I serve you by expiring
I vanish faster when I am thin
and slower when I am thick
The wind is my energy
What am I?

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?

During which month do people sleep the least?

I am a word of 12 alphabets.

* Alphabets 12, 4, 7, 2, 5 : Eastern beast of burden
* Alphabets 1, 8, 10, 9 are street made famous by Sinclair Lewis.
* Alphabets 11, 3, 6 are past.

On whole it means a person suffering from delusions of greatness.

What Is it ?

Two Twins Jack and Jill were standing back to back and suddenly they started running in opposite direction for 4 kilometres and then turn to left and run for another 3 kilometres.

what is the distance between the Baggio twins when they stop ?

Name one eight-letter word with 'kst' in the middle, 'in' the beginning, 'and' at the end.?