The proportional relationship between the number of hours a business operates and its total cost of electricity is shown in the following graph. Which statements about the graph are true? Choose all answers that apply: A The y-coordinate of point A represents the total cost of electricity when the business operates for 4 hours. B The total cost of electricity is $35 when operating the business for 1 hour. C None of the above

The biologist has a second culture to examine. she knows that the population of the culture doubles every 15 minutes. after 1 hour and 15 minutes, her assistant found that 80,000 bacteria were present. a) what was the size of the initial population? b) predict the size of the culture at t=3 hours. what was the size of the population at 40 minutes? explain and justify your answers. c) create a graph of the population as a function of time. find an equation that can be used to predict the size of the population at any time t. d) examine the rate at which the bacteria culture is growing. how fast is the culture growing after 1 hour? after 1.5 hours? after 2 hours? use a time interval of h = 0.01 hours to estimate these rates. interpret these rates in terms of the context of the problem situation. how do these three rates compare?