An unknown radioactive element decays into non-radioactive bstances. In 720 days the radioactivity of a simple decreases by bid percent. (a) what is the half-life of the element? half-life (days) (b) How long will it take for a sample of 100 my to decay to 61. my? time needed: idays mil . As. .. . The half-life of caffeine in the human body is about 5.6 hours. A cup of coffee has about 115 mg of caffeine. a. Write an equation for the amount of caffeine in a person's body after drinking a cup of coffee? Let c be the miligrams of caffeine in the body after & hours. b. How much caffeine will remain after 10 hours? State your answer to the nearest hundredth of a my. C. How long until there are only 20 my remaining! hours State your aniver to the nearest hundredth of an hour. waitidle purchased for $:42500) depreciate at a constant note of 1315 mach your. Its value after I years con be modeled by the equation A = P[0.57]', where P is the original vive of the vehicle. Determine the recber of years that it bikes for the vehicle to depreciate to SHUOU found to the nearest booth. Solve the equation guen. Exter all solutions, in degrees, that be in the interval |0",:160'). Do not enter the degree sign. If there are more than one angle, separate them by a comma. doas y - 1 easy + 5 - 0 Find an angle o with 0