Răspuns:
Explicație pas cu pas:
4c_____2s_____32 ron
2c_____6s_____56 ron /x2
______________________
4c_____2s_____32 ron
4c_____12s____112 ron
_____________________
//______10s_____80 ron
1s=80:8
1 stilou=10 lei
4c+10x2=32
4c+20=32
4c=12
1c=12:4
1 caiet=3 lei
proba: 4x3+2x10=12+20=32