The energy released from glucose during this reaction is used and also wasted. Some of the energy is used as work while some amounts are used in other processes or stored for transfer to other organisms. Also, some of the energy is wasted in the form of heat.
To do this problem you need to use the equation which is Speed= distance/time and this problem gives you the speed which is 18 km/h and it gives you the time 1/2 hour so you write the equation 18= d/ 1/2 which his distance is 9km