Question 250338
D=RT
2,100=R*5.6 
R=2,100/5.6
R=375 MPH. AGAINST THE WIND
2,100=R*4.8
R=2,100/4.8
R=437.5 MPH. WITH THE WIND.
(437.5-375)/2=62.5/2=31.25 MPH FOR THE WIND.
PROOF:
437.5-31.25=406.25 MPH FOR THE PLANE IN STILL AIR.
375+31.25=406.25 DITTO.