Suppose you travel \(10 \mathrm{~km}\) from \(\mathrm{P}\) to \(\mathrm{Q}\) at \(10 \mathrm{~km} / \mathrm{h}\) and another \(10 \mathrm{~km}\) from \(\mathrm{Q}\) to \(\mathrm{R}\) at \(20 \mathrm{~km} / \mathrm{h}\). What is your average speed during the entire trip from \(\mathrm{P}\) to \(\mathrm{R}\) ?