The question is not complete without a picture depicting the pot stickers production. I found a similar question with a table for the production of pot stickers which is attached to this answer. If the actual table is different from the table in this answer, you can still answer your question accordingly using my working and reasoning.
Answer:
Day 6
Step-by-step explanation:
It was given that the usual production of the kitchen is between 20 to 22 pot stickers per hour. Day 1 to 3, the production is within the range given.
However on day 4 and 5, the production is dropped to 10 and 15 - probably due to the workers unfamiliar with the machine.
On day 6 and 7, the production increases to 50 and 55. Therefore the day the machine makes positive impact is on day 6 where the production starts to make a significant increase.