Question 116160
DISTANCE=RATE*TIME.
OR T=DISTANCE/RATE.
BECAUSE THE TIMES ARE THE SAME WE HAVE THE FOLLOWING EQUATION:
400/(R+25)=320/(R-25) CROSS MULTIPLY.
400(R-25)=320(R+25)
400R-10,000=320R+8000
400R-320R=800+18,000
80R=18000
R=18,000/80
R=225 MPH FOR THE SPEED OF THE PLANE.
PROOF
400/(225+25)=320/(225-25)
400/250=320/(200)
1.6=1.6