at a sports day the school pupils participated and in a conetst, which was made out of 3 courses : runing,bicycle riding and swiming. the leangth of the swiming cours course was 20% of the leangth of the riding course.the runing course leangth was 1/5 of the swiming course. the combined leangth of all of those 3 courses was 62km. what was the leangth of each course?