Răspuns :
a+b=260
a=b-20
b-20+b=260
2b=280
b=280:2
b=140 timbre are Maria
a+140=260
a=120 timbre are Ana
a=b-20
b-20+b=260
2b=280
b=280:2
b=140 timbre are Maria
a+140=260
a=120 timbre are Ana