who many hours does a flight travel from Nigeria to London and from London to USA?

Lagos to London is about 7 hours of flying.

London to USA depends on where. London to New York is about 7 hours of flying and London to Denver is almost 10 hours of flying.

A direct flight from the capital of Nigeria, Abuja to London would be approx. 6 Hrs 44 Min. Then the flight from London to the East Coast of US is 7 Hrs 47 Min. You can get flight times for airports all over the world at https://www.jets.com/