Weight and Height

         There are two men. One is tall and the other is a midget. The tall man is two meters in height and the midget stands 1 metre high. By how much does the tall man outweigh the midget?

Answer:   The man who is twice taller outweighs the other not two, but eight times.

Sum of the Reciprocals

         The sum of two numbers is ten. Their product is twenty. Can you find the sum of the reciprocals of the two numbers? 

 Answer:    ½. this problem can be worked by simultaneous equations, but the solution shown below is a cleverer, more intuitive approach.

⅟ₐ + ⅟b = a+b/ab = 10/20   = ½