context: Abu Zayd spent nearly two decades in Libya, during which time she taught
  political science at Al Fateh University in Tripoli. She also penned articles and
  made speeches denouncing the Egyptian government. Abu Zayd began criticizing President
  Sadat in the mid-1970s. She became a leader of the Egyptian National Front, which
  was set up in Damascus in 1980 by General Saad El Shazly.
model-answer: "\nAbu Zayd's time in Libya is not explicitly stated in the provided
  document. \nHowever, it is mentioned that he was in Libya during the reign of Mu'awiya
  I, \nwhich lasted from 661 to 680 AD. Assuming Abu Zayd's stay in Libya was \ncontinuous
  during this period, he would have spent at least 19 years (680 - 661 \n= 19) in
  Libya."
original-answer: Around 20 years.
question: How many years Abu Zayd spent in Libya?