Question 1193865
<pre>
Start with 20, go down 1 at a time multiplying until you have 4 factors
on top.

Then there are also 4 factors on the bottom, starting with 4, going down 1
at a time until you have 4 factors on the bottom. 


like this:


{{{(20*19*18*17)/(4*3*2*1)}}}

Then figure that out.

Edwin</pre>