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

Buy me, smell me or deliver me, I do not change.

Who am I?

Which is the smallest number that you can write using all the vowels exactly once?

You have a roll of cloth 1km long. You have a machine which cuts this roll into pieces of 10-meter-long cloth.

How long would it take for the machine to cut the roll if each cut took 4 secs?

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

A man who was outside in the rain without an umbrella or hat didn’t get a single hair on his head wet. Why?

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 ?

Jack and Joseph are well-known golf rivals. One Day during a match, they were level at a score of 30. Jack hit a bad shot and Joseph added 10 to his score. Joseph then hit an awesome shot and he won the game.

How ?

A thief is convicted in Mexico. He gets the death penalty. The judge allows him to say the last sentence to determine how the penalty will be carried out. If the thief lies, he will be hanged, if he speaks the truth he will be beheaded. The thief tells the last sentence and to everybody's surprise some minutes later he is set free because the judge cannot determine his penalty. What did the thief say?

Take away my first letter, then take away my second letter. Then take away the rest of my letters, yet I remain the same. What am I?