Răspuns:
6pixuri...................7stilouri..............225 ron / ori 3
3pixuri....................5stilouri...............144 ron / ori 6
18pixuri................21stilouri...............675ron
18pixuri.................30stilouri............864ron
864-675=189
9stilouri ..............189ron
189:9=21
1stilou.........29ron
21ori30=630
864-630=234
18 pixuri..........234ron
234:18=13
1pix...........13ron
Rezolvare:1 pix=13 ron
1 atilou=29ron
SUCCES!!!