The maximum heart rate, in beats per minute, that you should achieve during exercise is 22...

The maximum heart rate, in beats per minute, that you should achieve during exercise is 220 minus your age:

The following bar graph shows the target heart rate ranges for four types of exercise goals. The lower and upper limits of these ranges are fractions of the maximum heart rate,220 − a. Exercise are based on the information in the graph.

If your exercise goal is to improve cardiovascular conditioning, the graph shows the following range for target heart rate, H, in beats per minute:

a. What is the lower limit of the heart range, in beats per minute, for a 20-year-old with this exercise goal?

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b. What is the upper limit of the heart range, in beats per minute, for a 20-year-old with this exercise goal?