Answer
5100
Work Step by Step
The sum of the first n integers is:
1 + 2 + ··· + n = $\frac{n(n + 1)}{2}$
Now,
$4+8+12+ . . . +200$
= $4\times1 + 4\times2 +4\times3 + .. .+4\times50$
= $4\times(1+2+3+...50)$
= $4\times\frac{50\times(50+1)}{2}$
(as $1+2+3+...50$ = $\frac{50\times(50+1)}{2}$)
= $2\times50\times51$
= 5100