Finite Math word problem

Question

To achieve the maximum benefit for the hear when exercising, the heart rate (in beats per minute) should be the target heart rate zone. The lower limit of this zone is found by taking 70 % of the difference between 220 and the age of the person. The upper limit is found by using 85% of the difference. Find the formulas and lower limits as linear equations involving the age x.

Answer 1

lower limit = 70% (220 - x) = .7(220 - x) = 154 - .7x

 

upper limit = 85% (220 - x) = .85(220 - x) = 187 - .85x