17. The master and the apprentice work together to process 765 parts. The master works for 4 days first, then the apprentice works for 7 days to complete the task. If the apprentice works for 2 days first, and then the master works for 6 days, the task can also be completed. How many parts does the apprentice process each day?
Analysis: The test point is an engineering problem
The master first worked for 4 days, then the apprentice worked for 7 days to complete the task;
The apprentice first worked for 2 days, then the master worked for 6 days to complete the task

Through equivalent substitution, it can be found that the master's 2 days of work equals the apprentice's 5 days of work. Assuming the master's 2 days of work is 10 units, then the master's efficiency is 5 units/day, and the apprentice's efficiency is 2 units/day. The total amount is $5 \times 4 + 7 \times 2 = 34$ units, then the number of parts the apprentice processes per day is: $765 \div 34 \times 2 = 45$ (units)