Question

The sum of the first 1000 positive integers is ___.

• A. 50051
• B. 500500
• C. 50050
• D. 5005

Answer 1

The correct option is B

500500

The first 1000 positive integers are 1,2,3,4....., 1000.

$\Rightarrow n=1000$

The sum of first $n$ natural numbers is given by
$S_n=\frac{n(n+1)}{2}.$

$\Rightarrow S_{1000}=\frac{1000\times 1001}{2}$

$=500\times 1001$

$=500500$