Answer: 15 packs per hour
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Work Shown:
y = change in number of packs sold
y = 57 - 12
y = 45 packs
x = change in time (in hours)
x = 3 hours
m = slope = rate of change
m = y/x
m = 45/3
m = 15
The store sold 15 packs per hour during the timespan of noon to 3:00 pm.
