There was an aeroplane crash, every single person died, but two people survived. How is this possible?

How will you measure 15 minutes using two hourglasses of 7 minutes and 11 minutes respectively?

There are two candles. Both will only burn exactly for an hour. How will you use these two candles to measure forty-five minutes?

Three doctors said that Bill was their brother. Bill says he has no brothers. How many brothers does Bill actually have?

In the below-given picture of a pretty girl, there is something wrong. Can you find out what it is?

There is a box full of marbles,
all but two are blue,
all but two are green,
and all but two are red.

How many marbles are in the box?

You’ll find me on Mercury, Earth, Mars, Jupiter, Saturn, and Uranus. But never Neptune, or Venus. What am I?

What is so fragile that saying its name breaks it?

A B C D E F G H

These are the letters given to you. Now you have to find out the letter that comes two to the right of the letter which is immediately to the left of the letter that comes three to the right of the letter that comes midway between the letter two to the left of the letter C and the letter immediately to the right of the letter F.

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?