The more of this there is, the less you see. What is it?

I have a hole in my back and legs I lack.
I live where I can’t breathe and I eat without teeth.
What am I?

I am a white box having no key or lid.
Yet there is a golden treasure inside it.

What Am I?

When my father was 31 I was 8. Now he is twice as old as me. How old am I?

I came first on earth but second on the heaven.
I also came twice in a week but found just once in a year.
I stay away from months but you can find me in February.

What am I?

John’s parents have three sons: Snap, Crackle, and what’s the name of the third son?

If 5 cats catch 5 mice in 5 minutes, how long will it take one cat to catch a mouse?

A monk has a very specific ritual for climbing up the steps to the temple. First, he climbs up to the middle step and meditates for 1 minute. Then he climbs up 8 steps and faces east until he hears a bird singing. Then he walks down 12 steps and picks up a pebble. He takes one step up and tosses the pebble over his left shoulder. Now, he walks up the remaining steps three at a time which only takes him 9 paces. How many steps are there?

Twice ten are six of us,

Six are but three of us,

Nine are but four of us;

What can we possibly be?

Would you know more of us?

Twelve are but six of us,

Five are but four, do you see?

What are we?

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?