Question

With a tailwind, a jet flew 2000 miles in 4 hours. The jet's return trip against the same wind required 5 hours. Find the jet's speed and the wind speed.

Answer 1

(jetspeed + windspeed) * 4 = 2000 = (jetspeed - windspeed)*5

Answer 2

Suppose that with no wind the jet's speed is v. Let the wind have speed w.

For the first leg of the trip, the speed of the jet is
v + w
because the wind is assisting the jet.

Now, speed = (distance)/(time) hence
v + w = 2000/4 = 500

For the return trip, the speed of the jet is
v - w
because the wind is working against the jet.

Hence
v - w = 2000/5 = 400

Therefore you have two simultaneous equations:

v + w = 500
v - w = 400

Now solve them to find v and w.