d=3h and d=5r, since d=d
3h=5r and we are told that h+r=3 so r=3-h making the equation become:
3h=5(3-h)
3h=15-5h add 5h to both sides
8h=15 divide both sides by 8
h=1.875 hrs (1:52:30)
So Stu hiked for 1.875 hours. (1 hour 52 minutes and 30 seconds)
check...
3(1.875)=5(3-1.875)
5.625=5(1.125)
5.625=5.625 (and it also shows the that trail was 5.625 miles long)