Răspuns :
a + b = 420
a = |-----|
b = |-----|-----|
a = 420 : 3
a = 140
b = 140 x 2
b = 280
PROBA : 140 + 280 = 420
a = |-----|
b = |-----|-----|
a = 420 : 3
a = 140
b = 140 x 2
b = 280
PROBA : 140 + 280 = 420