Shannon takes her pulse for 20 seconds each and records 40 beats within this time. Work out her heart rate per minute using this data.

Sure, here are the steps to calculate Shannon's heart rate per minute:

1. First, we know that Shannon's pulse is 40 beats in 20 seconds.

2. We need to find out how many beats her heart makes in a minute. Since 1 minute is 60 seconds, we need to scale up the number of beats from 20 seconds to 60 seconds.

3. To do this, we divide 60 (seconds in a minute) by 20 (the number of seconds she counted her pulse). The result is 3.

4. Then, we multiply the number of beats she counted (40) by 3.

5. The result is 120 beats per minute.

So, Shannon's heart rate is 120 beats per minute.