A boy and a girl are sitting on the porch.
"I'm a boy," says the child with black hair.
"I'm a girl," says the child with red hair.
If at least one of them is lying, who is which?
There is a bag which have 21 blue balls and 23 red balls. You also have 22 red balls outside the bag. Randomly remove two balls from the bag. * If they are of different colors, put the blue one back in the bag. * If they are the same colour, take them out and put a red ball back in the bag. Repeat this until only one ball remains in the bag. What is the color of the sole ball left in the bag ?
There was a competition where the contestants had to hold something. At the end of the event, the winner was a person who had no hands or feet. What was it that the contestants had to hold?
In the attached figure, you can see a chessboard and two rooks placed on the chess board. What you have to find is the number of squares that do not contain the rooks. How many are there?