Răspuns :
2(a + b) = 60
a = 2b
2 * 2b + 2b = 60
6b = 60
b = 60 : 6
b = 10
a = 2 * 10
a = 20
a = 2b
2 * 2b + 2b = 60
6b = 60
b = 60 : 6
b = 10
a = 2 * 10
a = 20