Pale has a piece of string 24 centimetres long. He ties the ends together and then lays it out so that it makes a rectangle. He notices that the length of the long sides is twice the length of the short sides.
How long are the sides of the rectangle?
Solution:
A rectangle has four sides, with sides opposite eachother the same length.
Since we know that two short sides plus two long sides equals a total of 24 centimetres, we know that one long side plus one short side must be half that long - 12 centimetres.
We know that a long side is twice as long as a short side. A bit of guessing and checking tells us that the two numbers that work are 8 centimetres for the long sides and 4 centimetres for the short sides.