Question 319074
D=RT
D=2T
UP THE HILL.
D=8(1-T) DOWN THE HILL.
2T=8(1-T)
2T=8-8T
2T+8T=8
10T=8
T=8/10=.8 HOURS FOR THE RUN UP THE HILL.
1-.8=.2 HOURS FOR THE RUN DOWN THE HILL.
PROOF:
2*.8=8*.2
1.6=1.6 
1.6+1.6=3.2 MILES IS THE TOTAL DISTANCE UP & DOWN.