The probability that a certain slot machine will pay back money when a quarter is inserted is 0.30. Assume that each play of the slot machine is independent from each other. A person puts in 15 quarters for 15 plays.
- The mean grade on a math exam in Rachel's class was 74, with a standard deviation of 5. Rachel earned an 80.
- The mean grade on a math exam in Becca's class was 47, with a standard deviation of 2. Becca earned a 51.
- The mean grade on a math exam in Matt's class was 70, with a standard deviation of 8. Matt earned an 83.
Find whose score was the best, compared to his or her own class. Justify your answer numerically