When you enter into a loan contract with the school library, a fine of 10 times can be regarded as the liquidated damages in the contract. If you don't know that the penalty for losing books is 10 times the book price before signing the contract (that is, before borrowing books), then the agreement of 10 times the penalty will not have legal effect between you and the library.

However, if you know the liquidated damages of 10 times before borrowing books, then your agreement on liquidated damages has come into effect, and you can reduce your compensation according to Article 1 14 of the Contract Law, "If the agreed liquidated damages are excessively higher than the losses caused, the parties may request the people's court or arbitration institution to reduce them appropriately".