Celine jogged at an average speed of $5\text{km/h}$ from her home to the nearby park and jogged back at an average speed of $4\text{km/h}$ via the same route. If Celine took a total time of $54\min $, what is the distance between her home and the park? 
Overseas Competition->Knowledge Point->Counting Modules->Inclusion-Exclusion Principle