Răspuns:
S1
1. 15/20=3/4
2.75%×12
75/100×12
=9
4.2/3=6/x
2x=18
x=2/18
x=9
5. 5p......10 lei
8p.......xlei
5x=80
x=80/5
x=16 lei
S2
3. 3m.......12 zile
4m........x zile
3x=48
x=48/3
x=16