To answer this question, we need to remember some properties on rates of change.
Call x the rate of change of the jet and y the rate of the jetstream.
We have that: When flying against the jetstream, it means we have x - y as the rate of change, the jet travels 5600 miles in 8 hours, thus 700 mi/h.
When flying with the jetstream, it means x + y, as the new rate of change, the jet travels 3540 miles in 3 hours, thus 1180 mi/h.
With these information, we have the following system of equations:
Sum the equations:
2x = 1880
Divide both sides by a factor of 2
x = 940 mi/h
This is the rate of change of the jet.
Plugging this value on any of the two equations, you have:
x - y = 700
940 - y = 700
y = 240 mi/h
This is the rate of change of the jetstream.
