Answer:
boat speed 79 kph
stream speed 16kph
Explanation:
Let v be the still water velocity
Let s be the stream velocity
3(v - s) = 189
3v - 3s = 189
v - s = 63
v = 63 + s
5(v + s) = 475
5v + 5s = 475
5(63 + s) + 5s = 475
315 + 5s + 5s = 475
10s = 160
s = 16 km/hr
v = 63 + 16
v = 79 km/hr