National Education Corp. said it has filed...

National Education Corp. said it has filed a registration statement with the Securities and Exchange Commission for a public offering of $57.5 million in convertible subordinated debentures.

Jeffrey Brill, vice president and general counsel of the Newport Beach vocational education company, said proceeds of the offering will be used to help pay bank debt incurred when NEC acquired Deltak Inc. and Resource Systems International Inc. from Gulf+Western Inc.

The $89-million purchase of the two firms became final on May 6, Brill said.

Deltak is based in Naperville, Ill., and had 1985 revenues of $69 million. It provides training for data processors in the banking and financial services industry. Resource Systems is a Nashville, Tenn., firm which makes custom-designed training materials. It had 1985 revenues of $6 million.