Please write down steps with explanation, I'm confused. Thank you!

Your stomach is a chemical reactor. When you devour a fast food 99 special hamburger in about a minute, it acts like an instantaneous input of 325g of food entering the stomach. In response, the stomach starts producing gastric liquids (acids), which are continuously excreted into the stomach at a rate of 12.0mL/min as the hamburger is digested. The fluid also leaves the stomach to the small intestine at a flow rate of 12.0mL/min,so the volume of liquid in the stomach stays constant at 1.15L. The hamburger digestion rate constant is 1.33hr1. (a) What kind of ideal reactor would you model your stomach as? (b) What fraction of the hamburger's mass will remain undigested in your stomach one hour after you eat the hamburger