Last Week's Solution

Challenge question #44 (13/02/2017)

Junior Question

A man is blindfolded. There are $20$ coins on a table in front of him, and he is told that $6$ of the coins are facing heads up.

How can the man divide the coins into two piles, so that each pile contains the same number of heads?


Senior Question

Prove that $2\tan^{-1}\left(\tfrac{1}{3}\right)+\tan^{-1}\left(\tfrac{1}{7}\right)=\tfrac{\pi}{4}$.