50 cm: 1 / 4 4.5 DM: 90 cm 4 hours: 1 / 4 4.5 DM: 90 cm 4 hours: 1 / 4 4.5 DM: 90 cm 4 hours: 1 / 4 hours
50cm: 1 / 4m = 2:1 = 24.5dm: 90CM = 1:2 = 0.54 hours: 1 hour 20 minutes = 3:1 = 3
Simplification ratio: 3 / 4 hours
=35: 45
=35:45
=7:9
() minutes: 4 hours, and 1:6 after simplification
40 minutes: 4 hours = 1:6