Question 280688
This problem uses the distance equation:  d = rt.
.
Ship r = unknown
t = 56 = 50 hrs head start + 6 hours it took the plan to catch up
d = 2400 km because the plane flew for 6 hours at 400 kmh to catch up
56r = 2400
.
d = rt
r = d/t
.
r = 2400 km/56 hr = 42.8571 kmh = speed of the ship
.
Done.