se aplica regula de 3 simple
12m....................10h....................18z
1m.....................10h.....................12.18
1m ......................1h.........................12.18.10
15m.......................1h.............................(12.18.10)/15
15m.........................9h............................(12.18.10)/(15.9)=16 zile
te rog sa zici daca e corect ca ma incurca treaba cu dupa 5 zile