To determine who worked at the highest intensity level, we need to compare each friend's average heart rate during the spin class (170 bpm) to their target heart rate zones.
- Janna's target zone: 146 bpm - 188 bpm
- Shania's target zone: 145 bpm - 188 bpm
- Paige's target zone: 140 bpm - 182 bpm
- Mimi's target zone: 140 bpm - 185 bpm
Now, let's see where the average heart rate of 170 bpm falls within each person's target heart rate zone:
- Janna: 170 bpm is within 146 bpm - 188 bpm (Her intensity level is within the zone).
- Shania: 170 bpm is within 145 bpm - 188 bpm (Her intensity level is within the zone).
- Paige: 170 bpm is within 140 bpm - 182 bpm (Her intensity level is within the zone).
- Mimi: 170 bpm is within 140 bpm - 185 bpm (Her intensity level is within the zone).
To find out who worked at the highest intensity, we look at the upper limits of each person's target zone:
- Janna's upper limit: 188 bpm
- Shania's upper limit: 188 bpm
- Paige's upper limit: 182 bpm
- Mimi's upper limit: 185 bpm
Since both Janna and Shania have the highest upper limit of 188 bpm and are within their zones while averaging 170 bpm, we need to identify who among them was at a relatively higher intensity.
However, both Janna and Shania were able to work at the maximum level of their respective zones. Since they both have the same upper limit and averaged the same heart rate (170 bpm), we can conclude:
Janna and Shania worked at the highest intensity level based on their maximum heart rate zones.
To answer the question directly, if we must choose one individual from the options provided, we would say:
Shania or Janna (either could be considered correct due to similar intensity levels).