What if i participate in an unrated competition on codechef

1)if i participate in the long challenge for this month (july 2021) , which is only rated for div 3 , and im in div 2 , will wrong submissions or less submissions(i.e. not answering most questions in that div correctly ) result in decrease of my rating ?

  1. also , what is the difference between scorable and non-scorable problems in div 2?

U will retain ur current ratings only no matter whatever u do.
scorable problem means it will give u points so that it can be viewed in leaderboard each scorable point adds 100 to ur total points(not rating only in contest total points) and nonscorable problems add 0 points.