What is the remainder when 2 + 4 + 6 + ... + 100 + 102 + 104 is divided by 7?
Remainder is 3
sumfor(n, 2/2, 104/2, 2*n)==2756 mod 7 == 5 - the remainder
Number of terms in the series = (104 - 2) / 2 + 1 = 51 + 1 = 52
Sum of the series =
(2 + 104) * (52) / 2 =
53 * 52 =
2756
2756 mod 7 = 5
