ok so
A to B=4 and 2/3
she sailed 3 and 1/3
how far was she from destination (how far more does she have to travel)
3 and 1/3+how much farther=4 and 2/3
subtract 3 and 1/3 from both sides
how much farther=4 and 2/3-3 and 1/3
4 and 2/3=4+2/3
-3 and 1/3=-3-1/3 so
how much farther=4 +2/3-3-1/3=
4-3+2/3-1/3=
1+1/3
answer is 1 and 1/3 miles more