Răspuns :
b : c = 1
b = c
80 : c = 2
2c = 80
c = 80 : 2
c = 40
b = 40
120 : a = b
ab = 120
a * 40 = 120
a = 120 : 40
a = 3
b = c
80 : c = 2
2c = 80
c = 80 : 2
c = 40
b = 40
120 : a = b
ab = 120
a * 40 = 120
a = 120 : 40
a = 3
80:c=20
c=80:20
c=4
80:4=20
b:c=1
b:4=1
b=4×1
b=4
4:4=1
120:a=b
120:a=4
a=120:4
a=30
120:30=4