p = 780
w = 180
You didn't provide a list of equations to select from, so let's see about creating them and solving. For this I'll use the variable p for the airspeed of the jet and w for the speed of the wind in the jet stream. So when the jet is traveling in the same direction as the jet stream, the ground speed is p+w and when the jet is traveling in the opposite direction, the ground speed is p-w. With that in mind, we can create two equations and solve them. The equations are:
(1). 1920 = 2(p+w)
(2). 1920 = 3.2(p-w)
Let's take equation (1) above and distribute the 2.
1920 = 2(p+w)
(3) 1920 = 2p + 2w
And do the same for equation (2) above.
1920 = 3.2(p-w)
(4) 1920 = 3.2p - 3.2w
Let's multiply (3) above by 1.6 to make the w terms equal in magnitude and opposite in sign to that in equation (4) above.
1920 = 2p + 2w
(5) 3072 = 3.2p + 3.2w
Add (4) and (5) above together, then solve for p
(4) 1920 = 3.2p - 3.2w
(5) 3072 = 3.2p + 3.2w
4992 = 6.4p
780 = p
So the Jet's speed is 780 km/h
Now use the speed of the Jet and (1) above to get the wind speed.
1920 = 2(p+w)
1920 = 2(780+w)
960 = 780 + w
180 = w
So the wind speed is 180.
