Consider the sequence in the form of groups (1), (2,2), (3,3,3), (4,4,4,4), (5,5,5,5,5),...
i. The 2000th term of the sequence is not divisible by
(A) 3 (B) 9 (C) 7 (D) None of these
ii. The sum of the first 2000 terms is
(A) 84336 (B) 96324 (C) 78466 (D)None of these
iii. The sum of the remaining terms in the group after 2000th term in which 2000th term lies is
(A) 1088 (B) 1008 (C) 1040 (D) None of these
The Attempt at a Solution
I don't know where to start!!
For ii, I need to find 1^2 + 2^2 + 3^2 + 4^2..... for which I have the formula n(n+1)(2n+1)/6, but I don't know what the preceding number of the group in which the 2000th term lies will be, so I can't even approximate an answer.
Just please tell me how to begin!