Answer:
[tex]\vec{a}=(10,18).[/tex]
[tex]2\sqrt{106}\approx20.6\ km.[/tex]
Step-by-step explanation:
Let the initial Caroline's location be at the origin (0,0) and the directions be:
1. Caroline walks 13 km due east, then her location is (13,0).
2. Caroline walks 18 km to the north, then her location is (13,18).
3. Caroline walks 3 km west, then her location is (10,18).
Thus, the component form of the vector containing her final destination is
[tex]\vec{a}=(10,18).[/tex]
If Caroline’s friend travels the shortest root to the cache, she will walk
[tex]\sqrt{10^2+18^2}=\sqrt{10+324}=\sqrt{424}=2\sqrt{106}\approx20.6\ km.[/tex]