50 dm/detik=………km/menit

50DM=50÷10.000=0,005KM
50detik=50÷10.000=0,005menit

50 x [(1/10000)/(1/60)]
50 x [(1/10000)*(60/1)]
(50 x 60) ÷ 10000
3000 ÷ 10000
0,3 km/menit