There are 20 people in an empty, square room. Each person has full sight of the entire room and everyone in it without turning his head or body, or moving in any way (other than the eyes). Where can you place an apple so that all but one person can see it?

Analyze and find the missing item in the sequence:
16, 06, 68, 88, __, 98

How can you take 2 from 5 and leave 4?

It comprises roots which nobody sees,
Much taller than those trees,
Up and up it goes,
Still it never grows?

Find The Next Number in the series:

12 13 15 17 111 113 117 119 123 ?

Transform the word THINK into BRAIN while changing only one letter at a time in a manner that each of the word in the process is a real word!!!

You see a boat filled with people, yet there isn’t a single person on board. How is that possible?

I can sizzle like bacon,
I am made with an egg,
I have plenty of backbone, but lack a good leg,
I peel layers like onions, but still remain whole,
I can be long, like a flagpole, yet fit in a hole.

What is the Surname of Barbie Doll?

Here is a mathematical expression that also secretly tells a movie name. What movie is that?