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

A man plots the murder of his wife. His plan is full proof. Nobody saw them leaving their house. He stabbed her with a knife while driving. She died on the spot. He threw her body in a valley. He threw the knife carefully wiping his finger prints on a random garbage bin. Then he went back to his home and no one was watching him this time as well.

After an hour, he was called by the local police department who informed him that his wife was murdered. They asked him to reach the scene of crime immediately. But as soon as he arrived at the crime scene, he was arrested by them.

How did the police know that he himself is the murderer?

There are are five things wrong with this sentence; only geniuses will be able to to spot all of the mitstakes

Find three numbers such that

* When we multiply three numbers, we will get the prime numbers.
* The difference between the second and the first number is equal to the third and second.

Assume there are approximately 5,000,000,000 (5 billion) people on Earth. What would you estimate to be the result, if you multiply together the number of fingers on every person's left hand? (For the purposes of this exercise, thumbs count as fingers, for five fingers per hand.) If you cannot estimate the number then try to guess how long the number would be.

Which Burger Is Different in below image?

In 1990, a person is 15 years old. In 1995, that same person is 10 years old. How can this be?

Can you find the company name in the pictogram below?

There is a square of a particular number which when doubled, becomes 7 more than its quarter.

Can you find the number?

Which country gets ill every time?