How to crack 8-character password?

This is the assignment I have in my Cyber Security class

Each student needs to crack 1000 passwords, the number of passwords at each length is given. There is 1 password of 8 characters

I spent days in the univerisity library with 6-7 computers running at the same time but I was only able to crack 752 passwords

I'm thinking about using multiple containers to and start cracking simultaneously

Any suggestion?

The contraint is using John the ripper

PS: My …

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