ENEMY = 2 * LINK
LINK + 2 = HELL

Then what will be TAXI + HELL? Select from the options below:
a) ROTTEN
b) DANGER
c) HEAVEN
4) MORTAL

An American nightclub called 'The Coconut Grove' had a terrible fire in which over 400 people died. A simple design flaw in the building led to a high death toll. Subsequently, regulations were changed to ensure that all public buildings throughout the country eliminated this one detail, which proved deadly. What was it?

What is in seasons, seconds, centuries and minutes but not in decades, years or days?

Your last good ping-pong ball fell into a narrow metal pipe embedded one foot deep in concrete.
How can you get it out undamaged, if all the tools you have are your tennis paddle, shoe laces, and plastic water bottle, which does not fit into the pipe?

What jumps when it walks and sits when it stands?

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

Move four matchsticks to the below square to form three squares?

I have feet, but no legs. Which animal Am I?

No matter how little or how much you use me, you change me every month. What am I?

If 21x = 79x, what is the value of x?