If integer k is equal to the sum of all even multiples of 5 between 300 and 610, what is the greatest prime factor of k? Choose the correct option
A) 32 B) 7 C) 11 D) 13 E) 17
if we break down what the stem is asking what is the sum of all mult of 10 between 300 and 610.   using arithmetic progression to find n : 610 = 300 + (n - 1) 10   310+ 10 = 10n   320 =10n =&gt; n = 32   the sum would be: 32* mean   mean = [610 + 300] / 2 = 455   32*455   32
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If integer k is equal to the sum of all even multiples of 5 between 300 and 610, what is the greatest prime factor of k?