At one store, a DVD is on sale for 25% off regular price of $26.99. At another store, the same DVD is on sale for 30% off regular price of $29.99. Why should you buy the DVD at the first store? a. 30% is more than 25%
b. $26.99 is less than $29.99
c. 75% of $26.99 is less than 70% of $29.99

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?