A word I know has six letters it contains, remove one letter and 12 remain. What is 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?

Solve the following series:
AZ, GT, MN, __, YB

What has many teeth, but cannot bite?

Can you name three consecutive days without using the words Monday, Tuesday, Wednesday, Thursday, Friday, Saturday, or Sunday?

Who always enjoys poor health?

You have 10 balls with you. A friend of yours out of nowhere asks you to place those ten balls in five lines such that each of the lines has exactly 4 balls on them. He needs to check your intelligence. Prove him by doing the task.

I am five letter word that is under you.
If you remove my 1st letter, then I am over you.
If you remove my 1st and 2nd letters then I am all around you.

Who am I?

What two things can you never eat for breakfast?

One is to three as three is to five and five is to four and four is the magic number.
What is the pattern?