What has one letter and starts with an E?

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?

Which Burger Is Different in below image?

I have a clock(12-hour format) and both the needles of the clock overlap at 12:00.
After how much time, they will overlap again?

What demands an answer, but asks no questions

I am looking for a word that change both gender and number when i add the letter 'S'.

What Word am I Looking For ?

There are a number of books on a shelf. If one book is the 4th from the left and 6th from the right, how many books are on the shelf?

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

I am white when I am dirty, and black when I am clean. What am I?

The first two letters signify a male, the first three letters signify a female, the first four letters signify a great, while the entire world signifies a great woman. What is the word?