Step-by-step explanation:
One of the logarithm rules states the following:

For this problem, that means the following:

So now we have the following:

Rolling the log, we get the following:

I would suggest that you look up a conversion chart.
Answer:
9-1 or 1-9
Step-by-step - Explanation - He makes 9 jars every hour so look at the graph and find the answer above ^^^^^^^