each day a man meets his wife at the train station after work , and then she drives him home . she always arrives exactly on time to pick him up . one day he catches an earlier train and arrives at the station an hour early . he immediately begins walking home along the same route the wife drives . eventually his wife sees him on her way to the station and drives him the rest of the way home . when they arrive home the man notices that they arrived 30 minutes earlier than usual . how much time did the man spend walking ?
"as they arrived 30 minutes earlier than usual , they saved 30 minutes on round trip from home to station ( home - station - home ) - - > 15 minutes in each direction ( home - station ) - - > wife meets husband 15 minutes earlier the usual meeting time - - > husband arrived an hour earlier the usual meeting time , so he must have spent waking the rest of the time before their meeting , which is hour - 15 minutes = 45 minutes . answer : a"
subtract(const_60, divide(30, const_2))