Jawapan

2016-03-17T10:56:17+08:00
I-Irina
R-radu
M-Marian
I+R+M=750
I=30+R
M=4R
Inlocuim:
30+R+R+4R=750
6R=750-30
6R=720
R=120 timbre
I=30+120=150
M=4*120=480
Verificare: 120+150+480=750