Question 900339
A 3-element subset contains 3 of the characters in the set.
{a,b,c}
{a,b,d}
{a,b,e}
{a,c,d}
{a,c,e}
{a,d,e}
{b,c,d}
{b,c,e}
{b,d,e}
{c,d,e}