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?

Hint

Senior Question

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

Hint