Answer
a. B, A, C
b. C, B, A
Work Step by Step
The parallelogram rule is discussed on pages 28-29, and relative velocity is discussed on page 51.
Each boat's velocity relative to the riverbank equals the vector sum of its velocity relative to the water, and the water's velocity relative to the riverbank.
Boat B has the largest "eastward" component of resultant velocity (it is a hair longer than that of boat A) and will reach the opposite riverbank first.
Longer resultant vectors correspond to faster speeds relative to the riverbank. Boat C gives the fastest ride, though it ends up traveling a long distance and will travel a significant distance downstream.
