Use the Empirical Rule. The mean speed of a sample of vehicles along a stretch of highway is miles per​ hour, with a standard deviation of miles per hour. Estimate the percent of vehicles whose speeds are between miles per hour and miles per hour.​ (Assume the data set has a​ bell-shaped distribution.) Approximately % of vehicles travel between 61 miles per hour and 71 miles per hour.

(50 ) 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.