Question

The target heart rate is the heartbeat rate during aerobic exercise that provides a benefit to your heart. The target heart rate for a person exercising at 70% intensity is given by the equation y = 0.7(200 - x) where y is the target heart rate in beats per minute and x is the person's age in years. How old is a person with a target heart rate of 133 beats per minute? How old is a person with a target heart rate of 126 beats per minute?

Answer 1

A. x = 10 years

B. x = 20 years

Explanation:

Given:

y = 0.7(200 - x)

Where,

y = target heart rate in beats per minute

x = person's age in years

How old is a person with a target heart rate of 133 beats per minute?

y = 0.7(200 - x)

133 = 0.7(200 - x)

133 = 140 - 0.7x

133 - 140 = -0.7x

-7 = -07x

x = -7/-0.7

x = 10 years

B. How old is a person with a target heart rate of 126 beats per minute?

y = 0.7(200 - x)

126 = 140 - 0.7x

126 - 140 = -0.7x

-14 = -0.7x

x = -14/-0.7x

x = 20 years