Question

Medical researchers have determined that for exercise to be beneficial, a person’s desirable heart rate, R, in beats per minute, can be approximated by the formulas where a represents the person’s age. If the desirable heart rate for a man is 135 beats per minute, how old is he?

Answer 1

40 years old

Explanation:

R, in beats per minute, can be approximated by the formulas , where a represents the person's age.

R= 143 - 0.65a for women

R= 165 - 0.75a for men,