11. p=persoane;m=mese
in cazul unu p=2xm+9
in cazul doi p=3xm+1
deci: 2xm+9=3xm+1 si vom gasi m=8 mese
apoi p=2x8+9, deci p= 25 persoane
12. r=rafturi; c=carti
in cazul unu c=60+(r-1)x50
in cazul doi c=(r-4)x60
deci: 60+(r-1)x50=(r-4)x60 si gasim r=25 rafturi
apoi c=60+24x50=1260 carti
La 14 nu prea imi dau seama...
