A training job writes a line to its log every time someone checks on it. Each line records how many batches the job has finished so far. Logging begins at , by which point batches are already done, and the run ends at minutes.
| Time (minutes) | Batches finished |
|---|---|
The job clearly did not run at a steady pace — it sped up, then slowed down. Ignore that for a moment and answer one question:
What is the average rate of change of over the whole run, from to ?
Give your answer in batches per minute, rounded to two decimal places if needed.