Pronounced as one letter,
And written with three,
Two letters there are,
And two only in me.
I am double, I am single,
I am black blue and grey,
I am read from both ends,
And the same either way.

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 possess a head

I flaunt a tail

But I don't have mouth or legs

Can you find out who I am?

If I remove one from eleven it becomes Ten and if I remove one from nine also becomes Ten. How?

There is a five-letter word which has 3 consonants(all are same) and 2 different vowels.
Also, something wrong is associated with the word.

Can you name it?

I sleep during the day and fly at night, but I have no feathers to aid my flight. What am I?

On her drawing table, Sayna lit 12 coloured candles. A few seconds later she blew two candles off.

How many candles Sayna have at the end?

Two in a corner, one in a room, zero in a house, but one in a shelter. What is it?

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

When I get multiplied by any number, the sum of the figures in the product is always me. What am I?