/ reprezinta fractie,impartire
Prima zi: 2a/7
A doua zi:2/3(a-a/7)=2/3(7a-a)/7=2/3x6a/7=4a/7
A treia zi:1/2(a-2a/7-4a/7)=1/2(7a-2a-4a)/7=1/2xa/7=a/14
Ultima zi : 15
a=nr.probleme
a=2a/7+4a/7+a/14+15 (numitor comun 14)
14a=4a+8a+a+210
14a=13a+210
14a-13a=210
a=210 probleme a avut de rezolvat Alex