81 x 9 = 801. What must you do to make the this equation true?

In a competitive exam, each correct answer could win you 10 points and each wrong answer could lose you 5 points. You sat in the exam and answered all the 20 questions, which were given in the exam.
When you checked the result, you scored 125 marks on the test.

Can you calculate how many answers given by you were wrong?

It's a test that will check your IQ.

Suppose you have one 11 minute hourglass and one 13 minute hourglass.

Can you measure exactly fifteen minutes using them ?

Can you find the company name in the pictogram below?

Decode the below four famous ciphers:

8P of the SS
1M of the E
1S of the SS
60M in 1H

I am under you when I am whole.
I shift above you if you remove the first letter.
I come all around you if you remove the second as well.

Can you tell me who I am?

Make the seating arrangement of 10 children in such a way that there are 5 rows with 4 children in each row.

A man in a car saw a Golden Door, Silver Door and a Bronze Door. What door did he open first?

A woman is sitting in her hotel room and hears a knock at the door. She opens the door to see a man whom she’s never met before. He says, “I’m sorry, I have made a mistake, I thought this was my room.” He then goes down the corridor and into the elevator. The woman goes back into her room and calls security. What made the woman so suspicious of the man?

Which is the smallest number that you can write using all the vowels exactly once?