Can you find out who is the kidnapper in below Picture and why, Explain ?

What is black when you buy it, red when you use it, and gray when you throw it away?

A four-digit number (not beginning with 0) can be represented by ABCD. There is one number such that ABCD=A^B*C^D, where A^B means A raised to the B power. Can you find it?

I have teeth but i don't bite. Who Am I ?

How can you tell a raw egg from a hard-boiled egg?

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

What Am I?

There is a brick of gold and a brick of iron in a boat (both 10-inch blocks), if they are both dropped into the water which will make the water level higher?

In the four images below, can you find the odd one out?

O_er_t_o_

Complete the missing letters of the given word.

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