Given \(a : b : c = 3 : 4 : 7\). Let \(a = 3k\), \(b = 4k\), \(c = 7k\). Then \(a + b + c = 3k + 4k + 7k = 14k\). The question asks for ratio with 'x' which is not defined in the original problem, making this question incomplete. The answer would be 'None of these' due to insufficient information.