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
R-143 -0.65a for women
R-165 -0.75a for men,
where a represents the person's age. If the desirable heart rate for a woman is 130 beats per minute, how old is she?
a 84 years old
b. 57 years old
C. 37 years old
d. 20 years old
Please select the best answer from the choices provided.