## Normal laws, correlation and probability problem

Hello,
Let n distributions of school marks. Each distribution follow a normal law of the same average ( m ) and of the same sigma (s). These n distributions are quite correlated between them two by two, with the same r-squared (r2).
All the pupils pass n tests. If they obtain one mark (or more) below k, they will be penalize.
How to determine the % of the penalized pupils?
Thank you very much for your help.