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What is the sum of all natural numbers between 200 and 400 which are divisible by 7 ?

Options

  1. A6729
  2. B8712
  3. C8729
  4. D9276

Correct answer

C. 8729

Step-by-step solution

aligned & a=203 ; L =399 & ~L =a+(n-1) d & 399=203+(n-1) 7 & or 399-203=(n-1) 7 & or 28=n-1 n=29 & Sum = 29 2 [a+ L ] & = 29 2 [203+399]=8729 aligned

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