Adrug is administered intravenously at a constant rate of r mg/hour and is excreted at a rate proportional to the quantity present, with constant of proportionality k> 0.(a) set up a differential equation for the quantity, q, in milligrams, of the drug in the body at time t hours. your answer will contain the unknown constants r and k. q′=equation editorequation editor(b) solve this differential equation, assuming there is no drug in the body initially. your answer will contain r and k. q=equation editorequation