Count the number of triangles in the picture below:

What is the word or phrase?

If we add four times the age of John four years from now to five times his age five years from now we get ten times his current age.

How old will John be two years from now?

Our product and our sum always give the same answer. Who are we?

Before Mount Everest was discovered, what was the highest mountain in the world?

If we tell you that there is a relation between the numbers and letters in the given figure, can you analyze it and find the missing letter in the last box?

Can you place three balls such that the equation shown in the picture holds true?

Take away my first letter, then take away my second letter. Then take away the rest of my letters, yet I remain the same. What am I?

Which letter of the alphabet has the most water?

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?