A new factory worker is put to work assembling gadgets. He is fairly slow at first, but over a period of days gets much faster. His employer constructs the following table to evaluate is progress over the first 20 days he is on the job. Give an upper estimate for the number of gadgets the worker assembled the second 10 days on the job. (Use 2 intervals)
Number of days on the job: 0, 5, 10, 15, 20
Number of gadgets assembled per day: 8, 15, 20, 23, 24