quasars and distances

Question

What is the minimum size of a quasar that shows variations in brightness over a period of 36 hours? Express your answer in kilometers. 

Answer 1

See answer posted at

https://www.wyzant.com/resources/answers/301589/what_is_the_minimum_size_of_a_quasar_that_shows_variations_in_brightness_over_a_period_of_36_hours