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?

I had an infinite supply of water and 5 litres and 3 litres jars.

How would you measure exactly 4 litres in the least number of steps?

A Scientist was fifty years old in the year 2000 but he was forty years old in the year 2010. How can this be possible?

PS: It has a logical answer.

A man lives on the fifteenth floor of an apartment building. Every morning he takes the elevator down to the lobby and leaves the building. In the evening, he gets into the elevator, and, if there is someone else in the elevator, or if it was raining that day, he goes back to his floor directly. Otherwise, he goes to the tenth floor and walks up five flights of stairs to his apartment. Can you explain why he does this?

I am weightless, but you can see me. Put me in a bucket, and I'll make it lighter. What am I?

A finger goes in me. You fiddle with me when you're bored. The best man always has me first. What am I?

Can you find out which options fits best with the missing column?

They are the five precious gems of an everyday sort and all can be found on a Tennis Court. Who are they?

I travel all around the world but always stay in the corner. What am I?

By removing one matchstick and adding one matchstick, can you convert the word "ZOO" to an animal name?