You can put this solution on YOUR website! Convert speed to km/min and multiply:
(2 km/hr)(1hr/60 min)=2/60 km/min
(2/60 km/min)(15 min)=30/60 km=1/2 km
OR
Convert time to hours and multiply:
(15 min)(1 hr/60 min)=15/60 hr=0.25 hr
(2 km/hr)(0.25 hr)=0.5 km= 1/2 km