a + b + c = 141
c = a/2 => a = 2c
(b - a) : (a + c) = 3 rest 1
b - a = 3(a + c) + 1
b - a = 3a + 3c + 1
b = 4a + 3c + 1
b = 4 * 2c + 3c + 1
b = 11c + 1
2c + 11c + 1 + c = 141
14c = 141 - 1
c = 140 : 14
c = 10
a = 2 * 10
a = 20
b = 11 * 10 + 1
b = 111
a * b * c = 20 * 10 * 111 = 22200
ultima cifra a produsului este 0