Using diaries for many weeks, a study on the lifestyles of visually impaired students was conducted. the students kept track of many lifestyle variables including how many hours of sleep were obtained on a typical day. researchers found that visually impaired students averaged 9.87 hours of sleep, with a standard deviation of 1.1 hours. assume that the number of hours of sleep for these visually impaired students is normally distributed. a. what is the probability that a visually impaired student gets less than 6.1 hours of sleep? b. what is the probability that a visually impaired student gets between 6.5 and 7.89 hours of sleep?

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.