Question 344122
D=RT
490=(R+20)T
T=490/(R+20)
330=(R-20)T
T=330/(R-20)
490/(R+20)=330/(R-20) CROSS MULTIPLY.
490(R-20)=330(R+20)
490R-9,800=330T+6,600
490R-330R=6,600+9,800
160R=16,400
R=16,400/160
R=102.5 MPH IS THE PLANES SPEED IN STILL AIR.
PROOF:
490/(102.5+20)=330/(102.5-20)
490/122.5=330/82.5
4=4