Find the odd one out
A tank can be filled by a pipe P in 32 minutes and by pipe Q in 36 minutes. When it is full, it can be emptied by a pipe R in 20 minutes. If all the three pipes are opened simultaneously, half of the tank will be filled in ____.
55 \( \frac{3}{13} \) hours
55 \( \frac{3}{25} \) hours
55 \( \frac{5}{13} \) hours
55 \( \frac{2}{5} \) hours