The function y = 100(0.5) x /4 models the percent, y, of an initial dose of medicine remaining in a patient bloodstream after x hours. what percent of the initial amount of medicine will remain in the patient’s bloodstream after 10 hours?

Rick is driving to his uncles house in greenville,which is 120 miles from ricks town .after covering x miles rick she's a sign stating that greensville is 20 miles away. which equation when solved will give the value of x. a: x+120 = 20 b: x x120 =20 c: x +20 equals 120 d: x x20= 120