Yumi picks up litter for 3 miles and takes two hours longer than juan, who picks up litter for 2 miles.
if it took juan x hours, his rate is 2/x
So it took Yumi x+2 hours,her rate is 3/(x+2)
Because both them have same rate 2/x=3/(x+2)
2(x+2)=3x
x = 4
It takes Yumi 6 hours.