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 lots of eyes, but can’t see?

Krish is 45 years old and his mother Crishtina is 73 years old.

Can you find out how many years ago, his mother was three times his age?

You need to pick one entry from pot A and one from pot B to have a perfect match. Can you do it?

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?

A man is trapped in a room. The room has only two possible exits doors. Through the first door there is a room constructed from magnifying glass. The blazing hot sun instantly fries anything or anyone that enters. Through the second door there is a fire-breathing dragon. How does the man escape?

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

Who am I?

Joseph buys three kinds of chocolates for 100 rupees. The first one is priced at 5 rupees, second one at 3 rupees and third one at 0.5 rupees.

If he bought 100 chocolates in total, how many pieces do you think he bought each chocolate?

Can you write down eight eights so that they add up to one thousand?

Can you make a six-letter word using the letters N, A and B ?