Question 999128
.
{{{C[15]^3}}} = {{{(15*14*13)/(1*2*3)}}} = 5*7*13 ways.


It is very standard test on Combinations.


See the lesson &nbsp;<A HREF=http://www.algebra.com/algebra/homework/Permutations/Introduction-to-Combinations-.lesson>Introduction to Combinations</A>&nbsp; in this site.