Human beings have a resting heart rate and an active heart rate. The resting heart rate is the rate at which the heart beats when a person is at rest, engaging in no activity. The active heart rate rises as activity rises. For a fairly active woman in her 20s, eight minutes of moderate exercise results in a heart rate of about 90 beats per minute. After 20 minutes, the same woman's heart rate will be about 117 beats per minute. If the human heart rate increases at a constant rate as the time spent exercising increases, which of the following linear models represents this same woman's heart rate, r, after t minutes of moderate exercise?
A. r = 0.15t – 5.3
B. r = 0.44t – 32
C. r = 2.25t + 72
D. r = 6.75t + 36
Answer:C
Human beings have a resting heart rate and an active heart rate. The resting heart rate is the rate at which the heart beats when a person is at rest, engaging in no activity. The active heart rate rises as activity rises. For a fairly active woman in her 20s, eight minutes of moderate exercise results in a heart rate of about 90 beats per minute. After 20 minutes, the same woman's heart rate will be about 117 beats per minute. If the human heart rate increases at a constant rate as the time spent exercising increases, which of the following linear models represents this same woman's heart rate, r, after t minutes of moderate exercise?
A. r = 0.15t – 5.3 B. r = 0.44t – 32 C. r = 2.25t + 72 D. r = 6.75t + 36
Explanation: C