What is the Surname of Barbie Doll?

It is a six-letter word.
The first four letters are me.
The second and last letters are the same.
The fourth second and last letter is payment.

Who is it?

Find the number of squares in the below-given picture.

What do you see in the given picture?

Manish and Manoj play 5 games of chess.
Both Manish and Manoj win the exact same number of games. There is no tie at all.

How?

Find the missing number in the image below.

The square root of number 121 is "11". What is the square root of the number "12345678987654321."?

If eleven plus two equals one, what does nine plus five equal?

What is the next number in this matchsticks series riddle?

A chicken farmer has figured out that a hen and a half can lay an egg and a half in a day and a half. How many hens does the farmer need to produce one dozen eggs in six days?