1)
I + A + F = 767
I = 6×A
F = 6×A
inlocuim in prima relatie in functie de a
6×A + A + 6+A = 767
13×A = 767
A = 767 : 13
A = 59 (pere) are Aurel
I = 6×59 = 354 (pere) are Ionel
F = 6×59 = 354 (pere) are Flavia
2)
a + b = 711
a - b = 65
adunam cele 2 relatii
2×a = 776
a = 776 : 2
a = 388
b = 711-388 = 323