Scientists are conducting trials on a new disinfectant for use in hospitals and doctor’s offices. After conducting several trials, they found that it decreases the presence of bacteria by 35% each second that it is applied to a surface. The next trial will apply it on a desk surface with approximately 20,000 cells of bacteria on it. Which logarithmic function models the time, , in seconds, it will take the number of cells to decrease to a value of n?

Mrs. julien’s and mrs. castillejo’s classes are selling cookie dough for a school fundraiser. customers can buy packages of macadamia nut chip cookie dough and packages of triple chocolate cookie dough. mrs. julien’s class sold 25 packages of macadamia nut chip cookie dough and 30 packages of triple chocolate cookie dough for a total of $221.25. mrs. castillejo’s class sold 5 packages of macadamia nut chip cookie dough and 45 packages of triple chocolate cookie dough for a total of $191.25. (a) write the system of equations that model the problem. be sure to explain which equation represents which situation. (b) find the cost of each type of cookie. show your work. (c) explain which method you used to solve the system and why you chose that method.