A cyclist practising for a road race found that one complete CIRCUIT of the course took exactly two hours and fifteen minutes. The course at one part was very hilly. His speed on the level was at the rate of 16 km/hr, uphill was 12 km/hr and downhill 24 km/hr. What is the distance round the course?
PS: I can't see why the answer is 36 km. This problem has 3 variables and only 2 equations, so I think it's not solvable. But I'm afraid it's tricky since the road race is CIRCUIT. For your reference, I got this problem from this site: http://cygnus.et.put.poznan.pl/~piotrw/rozneciekawe/zagadki.htm
PS: I can't see why the answer is 36 km. This problem has 3 variables and only 2 equations, so I think it's not solvable. But I'm afraid it's tricky since the road race is CIRCUIT. For your reference, I got this problem from this site: http://cygnus.et.put.poznan.pl/~piotrw/rozneciekawe/zagadki.htm