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Let ` x_1 , x_2 , x_3,....., x_k` be the divisors of positive integer n (including 1 and n). If `x_1 + x_2 + x_3 + ...... + x_k = 75` Then ` sum_(i=1)^k (1/x_i)` is equal to (A) `75/k` (B)`75/n` (C) `1/n` (D)`1/75`

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