If six children and two dogs were under an umbrella, how come none of them got wet?

A man escapes from jail using help from his girlfriend. The investigators suspect four girls of being the man's girlfriend.

Out of those four girls, one is his girlfriend who is lying. Two of the girls are completely innocent and are speaking the truth. One of the girls is the man's sister who is helping the girlfriend lie. Following are the statements from all four of them:

Ariana: "Myrna is his girlfriend."
Jane: "Angelina is lying."
Angelina: "Ariana is lying."
Myrna: "Jane is not his sister."

Can you find out who is the man's sister among them?

A number can be multiplied by multiple of nine
i.e 9 18 27 36 45 ...

and the resulting number consist of only one digit.

Can you identify the number ?

What have one eye but still cannot see?

If it took eight men ten hours to build a wall, how long would it take four men to build it?

John was working on a Chemical Mixture whose weight comprise 90% liquid and 10% solid. The total weight of the mixture is 20 pounds. After a while, John noticed that some of the liquid evaporated and now the liquid comprises just 50% of the weight.

What is the weight of the chemical mixture now?

I am white when I am dirty, and black when I am clean. What am I?

What is the fewest number of coins that would be required in order to make sure each and every coin touches exactly three other coins?

Replace the question mark with the correct number.

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