(a+b+c) : 3 = 115
a+b+c = 115×3 = 345
b = a - 25
c = 2×(a+a-25) = 4×a - 50
a +b + c = 345
inlocuim in relatie in functie de a
a + a - 25 + 4×a - 50 = 345
6×a = 345 + 75
6×a = 420
a = 420:6
a = 70
b = 70-25 = 45
c = 4×70-50 = 280 - 50 = 230
a = 70
b = 45
c = 230