a + b + c = 435
a : 6 = c r ==> a = 6×c+r
b : 7 = c r ==> b = 7×c+r
c : 8 = c r ==> c = 8×c+r
restul < 6
a + b + c = 6×c+r + 7×c+r + 8×c+r
435 = 21×c + 3×r | :3
145 = 7×c + r
pentru r = 5
7×c + 5 = 145
7×c = 140
c = 140 : 7
c = 20 (catul)
a = 6×20+5 = 125
b = 7×20+5 = 145
c = 8×20+5 = 165
Verificare:
125 + 145 + 165 = 435