Fine the distance in kilometres travelled by an areoplane moving at 150 km/h for 50 minutes
1 h = 60 min
1 min = 1 h / 60
50 min = 50 • 1 h / 60 = 50 h / 60 =
10 • 5 h / 10 • 6 = 5 / 6 h
150 km / 50 min = 150 km / ( 5 / 6 h ) =
6 • 150 km / 5 h = 900 km / 5 h =
180 km / h