Me i need answers for my sisters homework

Apatient is given 50 mg dose of medicine the medicines effectiveness decreases every hour at a constant rate of 40% what is the exponential decay function that models this scenario how much medicine will be left in the patients system after 2 hours

He that is measured at 220° is a reflex angle. the opposite angle is obtuse. find the measure of obtuse .

Find the smallest number by which the given number should be divided to make a perfect cube(with steps or the answer will get reported) a.108 b.2187