Can I get step by step explanation for question 11?

Greg and Frank went on a 10-day fishing trip. The number of smallmouth bass caught and released by the two boys each day was as follows: Greg 9 24 8 9 5 8 9 10 8 Frank 10 15 2 3 18 20 1 17 2 19 311. Assuming that the number of fish Frank caught are normally distributed (bell shaped), what is the probability he will catch between 18 and 26 fish the next time he goes fishing