We chose the first question: “How many golf balls were completed during January?”

Here’s what we know:

1. At the beginning of January, 10,000 golf balls were in work-in-process.

2. During January 20,000 more golf balls were started, so that means 30,000 golf balls passed through work-in-process in January (10K +20K).

3. At the end of January there were 6,000 balls in work-in-process.

Therefore, 24,000 golf balls must have exited work-in-process (30,000 minus 6,000)…i.e. 24,000 golf balls were completed during January.