Answer: 5 pints per hour
Explanation:
Morning:
3 pints every 4 minutes
3/4 pints every minute
(3/4 x 60) pints every hour -> 45 pints every hour
Afternoon:
2 pints every 3 minutes
2/3 pints every minute
(2/3 x 60) pints every hour -> 40 pints every hour
Difference in the rates between morning and afternoon:
(45 - 40) pints every hour -> 5 pints every hour