Question

A boat goes 30 km upstream and 44 km downstream in 10 hours .In 13 hours, it can go 40 km upstream and 55 km down-stream. Determine the speed of the stream and that of the boat in still water.​

Answer 1

Let the speed of boat in still water=x km\hr and The speed of stream=y km\hr

Speed of boat at downstream

⇒(x+y)km/hr

Speed of boat at upstream

⇒(x−y)km/hr

∵time=

speed

distance

Time taken to cover 30 km upstream ⇒

x−y

30

Time taken to cover 44 km downstream⇒

x+y

44

According to the first condition,

⇒

x−y

30

=

x+y

44

=10

Time taken to cover 40 km upstream ⇒

x−y

40

Time taken to cover 55 km downstream ⇒

x+y

55

According to the second condition,

⇒

x−y

40

...