3 Types of Economies. Market, Planning, and Mixed: SHORT STORY # 54. Nonfiction series #1- # 60

There are 3 types of economies: market, planning, and mixed.  The story gave definitions and introduced advantages and disadvantages of each type of economy.

The author lived under all 3 types of economies: planning (in the former Soviet Union), mixed (in Africa: Rwanda and Tanzania), and market (in the USA).

Why countries chose to have a Market, or Planning, or Mixed economy?

In reality, there in no one country in the world that has only a poor market economy, or poor mixed economy, or poor planning economy.  Why?  Please find answers in this story.