Even Sum

How many ways can we select 2 distinct integers from

{ 1 , 2 , 3 , , 99 } \{ 1, 2, 3, \ldots, 99 \}

such that their sum is even?

( 49 2 ) + ( 50 2 ) { 49 \choose 2 } + { 50 \choose 2 } ( 99 2 ) {99 \choose 2 } ( 99 2 2 ) { \frac{99}{2} \choose 2 } ( 99 2 ) 2 \frac { {99 \choose 2 } } { 2}

This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try refreshing the page, (b) enabling javascript if it is disabled on your browser and, finally, (c) loading the non-javascript version of this page . We're sorry about the hassle.

0 solutions

No explanations have been posted yet. Check back later!

0 pending reports

×

Problem Loading...

Note Loading...

Set Loading...