\"\"

\

The combination is \"\".

\

The combinations formula is   \"\".

\

\"\"                              (Apply combinations formula)

\

\"\"                    (\"\")\"\"

\

\"\"                    (Expand \"\")

\

\"\"                    (Cancel common terms) \ \

\

\"\".                                       (Multiply: \"\")\"\"

\

The total  number of combinations are 462.