Question

A boat travels 60 km upstream

(against the current) in 5 hours.
The boat travels the same distance
downstream in 3 hours. What is the
rate of the boat in still water? What
is the rate of the current?​

Answer 1

16 km/h ….. still water boat rate

4 km/h …. Current rate

Explanation:

The speed of the boat supposed to be x km/h

The current rate is y km/h

(x + Y) * 3 = 60

(x – y) * 5 = 60

3x + 3y =60 ….. ①

5x – 5y = 60 ….. ②

① * 5 … 15x + 15y = 300 … ①’

② * 3 … 15x – 15y = 180 … ②’

①’- ②’ … 30y = 120

Y = 4 km/h …. Current rate

15x = 300 – 15*4 = 240

X = 16 km/h ….. still water boat rate