The graph model, the y axis begins at 0 and counting in 10s ends at 130, the x axis begins at 0 and ends at 10. In the model graph her heart rate is at 70 and it rises to 130 on the y axis; on the x axis it dips on 10. Bristol's heart rate, in beats per minute (bpm), over time in minutes during the last 10 minutes of yoga class. Bristol's resting heart rate is 70. Select the correct answer from the following. Show your work
a) Bristol's heart rate reaches a maximum rate of 120 bpm
b) It took Bristol 10 minutes to reach her maximum heart rate
c) At the end of the yoga class, Bristol's heart rate returned to her resting heart rate
d) After 8 minutes, Bristol's heart rate was 88 bpm
e) The graph that models Bristol's heart rate is a parabola
d) After 8 minutes, Bristol's heart rate was 88 bpm
To show work:
- At 0 minutes (resting heart rate): 70 bpm
- At 10 minutes (maximum heart rate): 130 bpm
- Rate of increase per minute: (130-70)/10 = 6 bpm
- After 8 minutes: 70 + (6*8) = 70 + 48 = 118 bpm
Therefore, after 8 minutes, Bristol's heart rate was 118 bpm, not 88 bpm. So the correct answer is not d) and may be one of the other options.