from my AP calculus class, just decided to tackle the over spring break hw and realized i never #$%#ing learned this shit 1. Suppose that a cup of cocoa cooled from 90 degrees C to 60 degrees C after 10 minutes in a room whose temperature was 20 degrees. How much longer would it take the cocoa to cool to 35 degrees C? 2. A radioactive substance decays at a rate proportional to the amount present. If one gram of a radioactive substance reduces .25 gram in four hours, find how long it will be until .1 gram remains. 3. A pizza heated to a temperature of 350 degrees Fahrenheit, is taken out of an oven and placed in a 75 degree F room at time t=0 minutes. The temperature of the pizza is changing at a rate of -110e^.4t degrees Fahrenheit per minute. To the nearest degree, what is the temperature of the pizza at time t=5 minutes?