奥数题the extra time ,in minutes,that is would take to cover a distance of 120kmtravelling at an average speed of 60km/h instead of 72km/h would be-----------
问题描述：
奥数题the extra time ,in minutes,that is would take to cover a distance of 120km
travelling at an average speed of 60km/h instead of 72km/h would be-----------
答