) Suppose that R = R(t) represents the number of people who know about a rumor t days after it was started. One way that sociologists model the spread of a rumor is the following: the rate at which the number of people who know the rumor changes is proportional to the product of the number of people who know the rumor and the number of people who don’t. Suppose that in a town of 750 people, a rumor is spread and initially 50 people know it. Set up but do not solve an initial value problem that models this situation.