1. The problem statement, all variables and given/known data A certain piece of dubious information about phenylethylamine in the drinking water began to spread one day in a city with a population of 100,000. Within a week, 10,000 people had heard this rumor. Assume that the rate of increase of the number who have heard the rumor is proportional to the number who have not heard it. How long will it be until half the population of the city has heard the rumor? 2. Relevant equations (Possibly): Natural Growth equation: dx/dt = kx (where k is a constant) 3. The attempt at a solution I really have no clue how to do this. I've tried setting it up where dx/dt = k(100000 - x) and integrating, but I'm always left with two unknown constants.