Question
The sum of any seven consecutive natural numbers is
always divisible by which of the following numbers?Solution
Let the numbers are 'n', 'n + 1', 'n + 2', 'n + 3', 'n + 4', 'n + 5' and 'n + 6'.
Required sum = n + (n + 1) + (n + 2) + (n + 3) + (n + 4) + (n + 5) + (n + 6)
= (7n + 21)
= 7(n + 3)
So, the sum is always divisible by 7.
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