Question 352017
D=RT
1080=(R+20)T
T=1080/(R+20) FOR THE TRUIP WITH THE WIND.
1000=(R-20)T
T=1000/(R-20) FOR THE TRIP QGAINST THE WIND.
1080/(R+20)=1000/(R-20) CROSS MULTIPLY
1080(R-20)=1000(R+20)
1,080R-21,600=1,000R+20,000
1,080R-1,000R=20,000+21,600
80R=41,600
R=41,600/80
R=520 MPH. IS THE SPEED OF THE PLANE IN STILL AIR.
PROOF:
1,080/(520+20)=1,000/(520-20)
1,080/540=1,000/500
2=2