Uh oh! Wolfram|Alpha doesn't run without JavaScript.
Please enable JavaScript. If you don't know how, you can find instructions
here
.
Once you've done that, refresh this page to start using Wolfram|Alpha.
sum ( binom( k, 3 ) * binom( 20-k, 5-3 ) ), from k=3 to 18
sum ( binom( k, 3 ) * binom( 20-k, 5-3 ) ), from k=3 to 18
Natural Language
Math Input
Extended Keyboard
Examples
Upload
Random
