PLEASE HELP! I WILL MARK THE BRAINLIEST IF YOU HAVE THE CORRECT ANSWER!! When Sandy and Allen's mother decorates the house for a holiday by herself, it takes her 5 hours. When both Sandy and Allen help, the three can finish the job in 2.5 hours. When only Allen helps his mother decorate, it takes the two 3.5 hours. How long would it take Sandy to decorate the house by herself?

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.