The Guardian – Alex Bellos
“As we are almost midway through the Tour de France, I thought it would be a good moment for some bicycle puzzles. 1) The King of the Mountains went up the col at 15 km an hour and down it at 45 km an hour. It took him two hours in total. Assuming that the distance he travelled up and down are the same, how far is it from the bottom to the top of the col?” (more)