Răspuns :
b+f = 24
f = b+6
b+b+6 = 24
2b = 24-6
2b = 18
b = 18:2
b = 9
f = b+6
f = 9+6
f = 15
f = b+6
b+b+6 = 24
2b = 24-6
2b = 18
b = 18:2
b = 9
f = b+6
f = 9+6
f = 15