If you say my name, I will no longer exist. What am I?

I am looking for a word that change both gender and number when i add the letter 'S'.

What Word am I Looking For ?

What has one letter and starts with an E?

Do You See It?

I’m light as a feather, yet the strongest person can’t hold me for five minutes. What am I?

You enter your friend's room. He is not in his room. Although you see that on the bed there are two dogs, five cats, two giraffes and three pigs. Also, a couple of chickens and ducks are flying in the room.

Calculate the number of legs standing on the floor.

I know there are two methods by using three time the same number with a plus(+) operator , you can make sum as 60.

One of them is 20+20+20.

whats the other way ?

O_er_t_o_

Complete the missing letters of the given word.

How many letters are in the alphabet?

Manish has to secure 40% marks to pass his B.tech final exams.
He got just 40 marks and failed by 40-marks.

What is the maximum marks?