9514 1404 393
Answer:
9 pastries per hour
Explanation:
In the 7 hours after the first, the baker made 83 -20 = 63 more pastries. That rate is ...
(63 pastries)/(7 hours) = 9 pastries per hour
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Additional comment
We have chosen to interpret the question as asking for the slope of a line on a graph of pastries vs. hours. Such a graph would show you the baker started with 11 pastries already made, so didn't actually make 20 in the first hour.