Complete the following series. It.s very logical:

1, 4, 5, 6, 7, 9, 11, __?

The person who makes it has no need for it. He who purchases it does not use it. The person who does use it does not know they are. What is it?

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

What am I?

A word I know,
Six letters contain,
Subtract just one,
And twelve is what remains.

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 ?

This is a simple one. You just have to count the number of Fs in the given sentence.

Finished Files are the result of years of scientific study combined with the experience of years.

How many did you count?

I shave every day, but my beard stays the same. What am I?

Christina is older than Kareena and Karishma. Katrina is older than Karishma and younger than Kareena. If Kareena has a brother named John, who is older than Christina, who's the youngest?

1 + 9 + 8 = ?
considering, 28 + 8 + 92 = 10

What is the unique property of the following words ?
* Revive
* Banana
* Grammar
* Voodoo
* Assess
* Potato
* Dresser
* Uneven