I have looked up the 777-36N(ER) A6-ECO and according to the database the config is F8C42Y304. How do i know it's a three class from this info?
From the numbers: F8 means 8 first class seats, C42 is 42 business class, and Y304 is 304 economy class seats. More info on travel classes on Wiki:
Travel class - Wikipedia, the free encyclopedia