What is the greatest positive integer x such that 7^x is a factor of 343^10?\nOptions:\n(A) 5\n(B) 9\n(C) 10\n(D) 20\n(E) 30 OK. Let's think. Some random thoughts first:
User
343^10 = (7^3)^10 = 7^30 The answer: (E).
Assistant