Thanks for letting us know.

6!*7*6*6!*5! is correct. I'm guessing you saw the answer in the print book? It's possible that there was a typo there. Remember you can always review the question (plus the solution) by looking at the MC II-A homework.

You can also find answer keys online here: https://classes.areteem.org/static/MCIIASampleSyllabus.html