The input is not precisely defined. 1 - With the variant of 3 constant speeds we know: the whole ride lasted t = t1 + t2 + t3 = 304 minutes 1st stage t1 = 30 minutes at a speed of 12km / h 2nd stage t2 = 24 sec at a speed of 54km / hour 3rd stage t3 = t - (t1 + t2) we know the time here, but the speed is not determined. 2 - With the variant of regular alternation of 2 known speeds and times , the whole ride lasted t = 304 minutes 1st stage t1 = 30 minutes at a speed of 12km / hour, here we have to find the route traveled (a1 = 6km) 2nd stage t2 = 24 sec at a speed of 54km / hour, here we have to find out the route (a2), be careful here is the time in seconds how many times the 1st and 2nd stage was repeated in the total race x = t / (t1 + t2), if the whole ride lasted t minutes, then the distance traveled is equal to a = x * (a1 + a2) So, now I'm pretty messed up, with insufficient task assignment, I leave the numerical operations to the student and his independent elaboration of the TI. PS. Please publish the result and procedure in the supplement to this question.