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

Can you solve the equation by finding the value of
A) Horse
B) Cowboy boot
C) Horseshoe

In the Picture?

There was a minor accident with a doctor's son but the doctor noticed no major injury. After the treatment, the father of that doctors son is sitting with the son of the doctor without the doctor being in the room.

How can this be possible?

What 8 letter word can have a letter taken away and it still makes a word. Take another letter away and it still makes a word. Keep on doing that until you have one letter left. What is the word?

What is the next number in the series?

15 29 56 108 208 ?

What's the next in the series?

H, Be, F, S, Mn, Kr, In, Gd, Tl, ?

In the city of Brain Teasers, 5% of people do not list their phone numbers. Now if we select random 100 people from the phone directory, then how many people selected will have unlisted phone numbers?

It can't be seen, can't be felt, can't be heard, and can't be smelt.
It lies behind stars and under hills, And empty holes it fills.
It comes first and follows after, Ends life, and kills laughter.
What is it?

Identify Me

Hint1: I am a god
Hint 2: I am a planet
Hint 3: measurer of heat

John enters a small room. The Door Closes.
When the door opens, John is in a larger room.

Explain?