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

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

Explain?

Can you find out which triangle will have a bigger area among the following?
1. A triangle with sides 300, 400 and 500
2. A triangle with sides 300, 400 and 700

I am weightless, but you can see me. Put me in a bucket, and I'll make it lighter. What am I?

You are given 2 eggs.
You have access to a 100-storey building.
Eggs can be very hard or very fragile means it may break if dropped from the first floor or may not even break if dropped from 100th floor, Both eggs are identical.
You need to figure out the highest floor of a 100-storey building an egg can be dropped without breaking.
Now the question is how many drops you need to make. You are allowed to break 2 eggs in the process

Why Wine Glass Stem is so long?

A brand new Mobile Phone was on sale at 20% as a promotional offer. By what per cent must the Mobile price be increased to sell it at the original price again?

Find the last number in the series below:

voN luJ yaM raM ---

What has six faces, but does not wear makeup, has twenty-one eyes, but cannot see? What is it?

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?