Out of a total of N students at a school, the number of students who have seen a new television program increases at a rate proportional to the product of the number of students who have seen the program and the number of students who have not seen the program. If S denotes the number of students who have seen the program at time t, which of the following differential equations could be used to model this situation, where is a positive constant?

ks - kt ( N1)
-AS (N-S)
D - KS (- N)

Can someone pls ! pls answer all. no explanation needed..

If the discriminant if a quadratic equation is 4 which statement describes the roots?

Unaware that 35% of the 10000 voters in his constituency support him, a politician decides to estimate his political strength. a sample of 200 voters shows that 40% support him. a. what is the population? b. what is the parameter of interest? state its value c. what is the statistics of the interest? state its value d. compare your answers in (b) and (c) is it surprising they are different? if the politician were to sample another 200 voters, which of the two numbers would most likely change? explain