Suppose average annual rainfall in a city is 19.8 inches with a standard deviation 5

inches, and suppose that average annual rainfall is normally distributed. Hydrologists

consider the city to be in drought conditions when average annual rainfall is 10 inches or

less in a given year. Approximately how frequently will the city experience drought

conditions?

A. Once every 20 years.

B. Once every 30 years.

*C. Once every 40 years.

D. Once every 50 years.

E. Once every 100 years.

Explain Please