Hannah's Sweets The answer Step 1: Take the words from the question, and write it down as an equation - 6/n x 5/(n-1) = 1/3 Step 2: Multiply the 6 by the 5 and the n by the n-1. That gives you: 30/(n^2 - n) = 1/3 Step 3: Multiply the top-left by bottom-right and top-right by bottom-left Step 4: Subtract 90 from both sides, leading to your answer n^2 - n - 90 = 0

The answer You should create a table of four columns with the months at the top and the dates Cheryl gives after. "You can rule out some of the options. For Albert to have known the answer, he would have to have May and June as that is when 19 or 18 occur." The number 14 is the only one in both months but Bernard is now sure of the birth date. This means Bernard knows it is July 16.

The cruel exam question The answer The answer depends on what type of person you are. "In reality, if too many people overuse a common resource then everyone in the group suffers," said the professor who set it.

Why 5+5+5 doesn’t always make 15 The answer A student was marked down for using the solution 5+5+5, with the teacher noting the correct working out should be shown as 3+3+3+3+3 using the repeated addition strategy.