Please help me with the following problem - ideally in excel.

• Solve the following problems:
  • Problem 1: At Boston (Logan International Airport) the average security wait time is 20 minutes per flight (according to a Global Partners International September 2017 report). What is the probability that your wait time is less than 20 minutes for your flight?(Assume data is discrete and tracked in one-minute intervals.)
• What is the approach you took with each of the two problems and why?