The greatest common factor is 10. It is the biggest number that goes into 20 and 30 evenly.
~Silver
The answer is two and a half years.
The United States watched World War I from afar for two and a half years before entering and declaring a war against Germany on April 6, 1917. Before entering the war, United States was intent on keeping a neutral relationship between countries that are involved in the war.
Answer:
Cleisthenes is the answer.
