Question

A ship goes downstream from one port to another in 8 hours and covers the same distance upstream in 9 hours. If the speed of the stream is 3 km/hr, find the speed of the ship in still water. km/hr

Answer 1

Answer:

Step-by-step explanation:

Let speed of the streamer in still water= x km/hr

Speed of downstream =(x+2)km/hr

Distance between the ports =4(x+2)km.... (i)

Speed of upstream =(x-2)km/hr

Distance between the ports =5(x−2)km....(ii)

from Equation (i) and (ii)

4(x+2)=5(x−2)

4x+8=5x−10

x=18

∴ Distance between two ports =4(x+2)

=4(18+2)km=80 km

Answer 2

Answer:

Step-by-step explanation:

We will proceed as follows:

Let the speed of the ship in the still water be x km/hr and it is given that the speed of the stream is 3 km/hr.

Then, the speed of the ship upstream is (x−3) km/hr and the speed downstream is (x+3) km/hr.

Now, it is given that the time taken by the ship to cover a distance upstream is 9 hours and the time taken by the ship to cover the same distance downstream is 8 hours.

So, equating the distances in both the cases, we get:

(x+3)×8=(x−3)×9 (As distance = speed × time)

⇒8x+24=9x−27

⇒8x−9x+24=−27

⇒−x+24=−27

⇒−x=−27−24

⇒−x=−51

⇒x=51

Hence, the speed of the ship in still water =51 km/hr.