Answer:
Average Speed of Container ships is 8 km/h.
Explanation:
Let the Average speed of container ship be 'x'
Now Given:
An aircraft Carrier left 0.7 hours later traveling 1.4 km/h faster in an effort to catch up to it.
Hence speed of aircraft carrier =

After four hours the aircraft carrier finally caught up container ship.
Hence Total time taken by aircraft = 4 hrs.
Since aircraft left after 0.7 hours and after 4 hours it caught the container ship.
Hence time taken by Container ship = 4 + 0.7 = 4.7 hrs.
Now we will find the Distance traveled by both.
Distance can be calculated by product of time and speed.
Distance of aircraft =

Distance of container ship =

Since both of them are at same place hence distance travveled by both would be similar.
Hence,
Distance of aircraft = Distance of container ship
Substituting the values we get;

Hence Average Speed of Container ships is 8 km/h.