Question 219248
D=RT
D=(13R+R)6=14R*6=84R
D=(13R-R)7=12R*7=84R
ANY DISTANCE THAT IS A MULTIPLE OF 84 MILES IS A SOLUTION.
PROOF:
LET THE RATE OF THE WIND=1 MPH.
D=84*1=84 MILES.
84=(13*1+1)*6 
84=(13+1)*6
84=84
84=(13*1-1)*7
84=(13-1)*7
84=84
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LET THE RATE OF THE WIND=50 MPH.
84*50=(13*50+50)*6
4,200=(650+50)*6
4,200=700*6
4,200=4.200
4,200=(13*50-50)*7
4,200=(650-50)*7
4,200=600*7
4,200=4,200