Jawabanmu

2014-08-11T21:13:53+07:00
V = 20km/jam
t = 4 jam
s = ?
s = vxt
   = 20x4
   = 80 km
v = 50 km/jam
s = 80 km
t = s/v
  = 80/50
  = 1,6 jam = 1 jam 18 menit