Respuesta :

105 answer b is the answer

Answer : (b). 105 bpm

Explanation :

given that,

Age = 40 years-old

Resting heart rate = 75 bpm

We know that,

Maximum heart rate = 220- Age

Maximum heart rate = 220-40 = 180 bpm

Heart rate reserve = Maximum heart rate - Resting heart rate

Heart rate reserve  = 180 bpm - 75 bpm

Heart rate reserve = 105 bpm

Hence, this is the required solution.