Please Please help me

When you exercise, your pulse rate rises. Recommended pulse rates vary with age and physical condition. For vigorous exercise such as jogging, the inequality 0.7(220 – a) ≤ R ≤ 0.85(220 – a) gives a target range for pulse rate R (in beats per minute), based on age a (in years).


A. What is the target range for pulse rates for 31 years old? Round to the nearest whole number.



B. Your cousin’s target rate is in the range between 140 and 170 beats per minute. What is your cousin’s age?

Respuesta :

Answer:

A. 132 ≤ R ≤ 161

B. 20

Step-by-step explanation:

A. .7 (220-31) ≤ R ≤ .85 (220-31)

.7 (189) ≤ R ≤ .85 (189)

132.3 ≤ R ≤ 160.65


B. 140/.7 = 200             170/.85 = 200

the formula states (220 - age) and this must equal 200 as found above

so 220 - 200 = 20