Acleaning company charges x dollars per hour to clean floors and y dollars per hour to clean the rest of a house. • when the company spends 2 hours to clean floors and 3 hours to clean the rest of a house, the total charge is $80. • when the company spends 1 hour to clean floors and 4 hours to clean the rest of a house, the total charge is $100. which ordered pair represents the hourly charges to clean floors and to clean the rest of the house? a) (2, 12) b) (4, 24) c) (12, 2) d) (24, 4)

3.17 scores on stats final. below are final exam scores of 20 introductory statistics students. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 57, 66, 69, 71, 72, 73, 74, 77, 78, 78, 79, 79, 81, 81, 82, 83, 83, 88, 89, 94 (a) the mean score is 77.7 points. with a standard deviation of 8.44 points. use this information to determine if the scores approximately follow the 68-95-99.7% rule. (b) do these data appear to follow a normal distribution? explain your reasoning using the graphs provided below.