Answer
(a) 3.5 m/s, South
(b) 18 s
(c) 7.7 s
Work Step by Step
Let's take,
Passenger's velocity relative to the water = $V_{PW}$
Passenger's velocity relative to the boat = $V_{PB}$
Boat's velocity relative to the water = $V_{BW}$
The direction of the north is positive
(a) We know that,
$V_{PW}=V_{PB}+V_{BW}$ ; Let's plug known values into this equation.
$V_{PW}=1.5\space m/s+(-5\space m/s)=-3.5\space m/s$
$V_{PW}=3.5\space m/s$ South
(b) We can get the time it takes for the passenger to walk a distance of 27 m on the boat,
$t=\frac{27\space m}{V_{PB}}=\frac{27\space m}{1.5\space m/s}=18\space m/s$
(c) We can get the time it takes for the passenger to cover a distance of 27 m on the water.
$t=\frac{27\space m}{V_{PW}}=\frac{27\space m}{3.5\space m/s}=7.7\space s$
