For the first one it’s asking your how much lenias heart decreased in a six minute period. If lenias heart decreased 17 beats in 5 minutes you’d need to find out how much lenias heart decreased in a minute. How do you do this, you divide 17 beats by 5, which gives you 3.4 or 3.4 beats per minute. Add this to 17 and you get 20.4. Which is how much lenias heart rate decreased in six minutes.
The same for the next one. Divide 36 by 12 (which gives you 3 or 3 Farenheit) and that’s how much it dropped in one hour