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.
1 - (sum C(7,k)*C(33,7-k)*C(40-k,7), k=0 to 7)/C(40,7)^2
Natural Language
Math Input
Extended Keyboard
Examples
Upload
Random