Complete the table series riddle by finding the number that can replace "??".

Whats the next number in the below number sequence pattern.

You can hear me, but you can't touch or see me.

What am I?

If you remove one from eleven, it becomes ten. If you remove one from nine, it becomes ten.

How is this possible?

You board a train. The train will have to enter a tunnel soon. You are claustrophobic. Which place is the best for you to sit?

P is the father of Q and S is the son of R. T is the brother of P and has a daughter U. If R is the sister of P, then what is the relation between U, Q and S?

What is common among 11, 69, and 88?

During a secret mission, an agent gave the following code to the higher authorities
AIM DUE OAT TIE MOD

However, the information is in one word only and the rest are fake. To assist the authorities in understanding better, he also sent them a clue, If I tell you any one character of the code, you can easily find out the number of vowels in the codeword.

Can you find out the code word?

In a contest, four fruits (an apple, a banana, an orange, and a pear) have been placed in four closed boxes (one fruit per box). People may guess which fruit is in which box. 123 people participate in the contest. When the boxes are opened, it turns out that 43 people have guessed none of the fruits correctly, 39 people have guessed one fruit correctly, and 31 people have guessed two fruits correctly.
How many people have guessed three fruits correctly, and how many people have guessed four fruits correctly

What is the word or phrase below?
R | E | A | D