A)
a=140 m => 14000 cm => 14000 cm/2000 = 7 cm
b=120m => 12000 cm => 12000 cm/2000 = 6 cm
c=180m => 18000 cm => 18000 cm/2000 = 9 cm
U = a+b+c = 7+6+9 = 22 cm
B kannst Du jetzt selber ausrechnen