During one of my walks on the beautiful Jacksonville Beach, I come across 7 surfers over half a mile.

1. How many surfers should I expect to see during the 2.5 miles of walk?

2. What is the probability that i will see 20 or more surfers over 2.5 miles? (Do not use normal approximation)

3. What is the probability that i will see 15 or less surfers over 2.5 miles? (USE normal approximation)

How do I solve each while using formulas in Excel? Please provide