using four eights (8) and a one (1) and one mathematical symbol , create the number 100

What's the only room from which no one can enter or leave

How many bricks does it take to complete a building that is 15 feet wide, 30 feet deep, and 12 feet tall made of brick?

In four steps you need to move the word 'cold' From 'warm' by replacing one alphabet at a time such that every word formed at each step is acceptable in English Dictionary.

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

Mr Red Lives in the red house.
Mr Green Lives in the greenhouse.
Mr Yellow Lives in the yellow house.

Who lives in the Whitehouse?

What is the below Rebus indicate?

I know a ten-letter word in the English language which can be typed using only the top rows of the computer keyboard.

Pronounced as one letter,
And written with three,
Two letters there are,
And two only in me.
I am double, I am single,
I am black blue and grey,
I am read from both ends,
And the same either way.

You and your two friends are working in a multinational company. How can you three find out the average salary of you all without disclosing your own salary to the other two?