Notam : pixuri=p
caiete=c
Andreea: 6p+4c=72 lei
Mihai:10p+8c=132 lei
---------------------------------
8p+6c=?
Cat rest primeste de la 100 lei
6p+4c=72
10p+8c=132
--------------------(scadere)
4p+4c=60(impartim la 4)=>p+c=15=>p=15-c
6p+4c=72=>6x(15-c)+4c=72=>90-6c +4c=72=>90-2c=72=>2c=90-72=>2c=18=>c=18/2=>c=9
6p+4c=72=>6p+4x9=72=>6p+36=72=>6p=36=>p=36/6=>p=6
Deci, 8p+6c=8x6+6x9=48+54=102
Nu primeste rest!