Question: According to an article in The New York Times, 19 pigweed has acquired resistance to the weed killer Roundup. Let N be the number of acres, in millions, where Roundup-resistant pigweed is found. Suppose the relative growth rate, (1/N)dN/ dt, was 15% when N = 5 and 14.5% when N = 10. Assuming the relative growth rate is a linear function of N, write a differential equation to model N as a function of time, and predict how many acres will eventually be afflicted before the spread of Roundup-resistant pigweed halts.