During exercise, the recommended maximum heart rate in beats per minute is modeled by the formula M = 176 - 0.8A, where M is the maximum heart rate and A is the person's age. Approximately, at what age would you have a recommended heart rate in beats per minute of 135?

A. 25 years
B. 39 years
C. 51 years
D. 53 years

1 answer

First, we can set up the equation using the given information:

135 = 176 - 0.8A

Subtracting 135 from both sides, we get:

41 = 0.8A

Dividing both sides by 0.8, we get:

A = 51.25

Rounding down to the nearest integer, we get 51. Therefore, the answer is C. 51 years.