An assembler of computer routers and modems uses parts from two sources. Company A supplies 80% of the parts and company B supplies the remaining 20% of the parts. From past experience, the assembler knows that 5% of the parts supplied by company A are defedctive and 3% of the parts supplied by company B are defective. An assembled modem selected at random is found to have a defective part. Which of the two companies is more likely to have supplied the defective part?