A word I know has six letters it contains, remove one letter and 12 remain. What is it?

John speaks the truth only once a day in a week. Below are a few hints for you:

First: Days are Sunday, Monday and so on.
Second: One day he says, "I lie on Monday and Tuesday".
Third: On the next day, he says, "Today is either Thursday, Saturday or Sunday".
Fourth: On the next day, he says, "I lie on Wednesday and Friday".

Can you identify the day on which he speaks the truth?

If an electric train is travelling south, then which way is the smoke going?

Find the next number in the series?
2, 12, 36, 80, 150, 252, 392, _ ?

What does the below image rebus riddle means ?

My friends called me Iron59 because my parents are a chemist and a mathematician. What is my real name?

Replace the question mark with the correct number, given the pair of numbers exhibits a similar relationship?

? : 3839 :: 11 : 1209

You have a square. What you have to do is cut and reassemble the square such that you create a Red Cross sign that has the same volume as that of the square.

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

It belongs to you, but other people use it more than you do. What is it?