If eleven plus two equals one, what does nine plus five equal?

There was a blind man. He had four socks in his drawer either black or white. He opened it and took out two socks. Now the probability that it was a pair of white socks is 1/2.

Can you find out the probability that he had taken out a pair of black socks ?

A man hijacks an aeroplane transporting both passengers(8 of them) and valuable cargo. After taking the cargo, the man demands nine parachutes, puts one of them on, and jumps, leaving the other eight behind. Why did he want eight?

There are nine letters in the below-given diagram. You have to form a nine-letter word using these letters.

Can you think of any three-dimensional shape that comprises of exactly two surfaces?

Which three-digit number, made of consecutive digits, like 567, is 2 less than a cube and 2 more than a square?

Find a 9-digit number, which you will gradually round off starting with units, then tenth, hundred etc., until you get to the last numeral, which you do not round off. The rounding alternates (up, down, up ...). After rounding off 8 times, the final number is 500000000. The original number is commensurable by 6 and 7, all the numbers from 1 to 9 are used, and after rounding four times the sum of the not-rounded numerals equals 24.

With the help clues provided in the image, can you find the 5 digit key?

What does this below rebus puzzle mean?

Which alphabet is a part of our body?