There are three boxes of different sizes with three cupcakes inside each of the boxes in Christina's kitchen. At night her daughter wakes up and goes to the kitchen. She opens a box and eats all three cakes.
But in the morning Christina finds out that each box still had three cupcakes. How?
A tree doubled in height each year until it reached its maximum height over the course of ten years. How many years did it take for the tree to reach half its maximum height?
John had a bag containing colourful marbles. The colours are red, green and blue. The total number of marbles he had in his bag was 60. There are 4 times as many red marbles as green marbles. 6 more blue marbles than green marbles. How many marbles of each colour did John have?
In 2011, people playing Foldit, an online puzzle game about protein folding, resolved the structure of an enzyme that causes an Aids-like disease in monkeys. Researchers had been working on the problem for 13 years. The gamers solved it in three weeks.
