Question

a streamer goes downstream from one point to another in 7 hours and covers the same distance upstream in 8 hours. If the speed of the stream will be 2km/hr, find the speed of the streamer in still water and the distance between the points

Answer 1

speed of stream = 2 km/hr
let speed of boat (in still water) = x km/hr
while going downstream  his speed = x+2 km/hr
and going upstream = x-2 km/hr
now A/Q 

dis /x+2 = 7⇒ dis = 7 (x+2)  ......(1)
and dis / x-2 = 8 ⇒ dis = 8(x-2)  ............(2)
(1) =  (2)

7x + 14= 8x - 16  ⇒ x = 30 km/hr

and dis = 7(30+2) = 7 x 32 = 224 km

hope this helps

Answer 2

Answer:

Step-by-step explanation:

speed of stream = 2 km/hr

let speed of boat (in still water) = x km/hr

while going downstream  his speed = x+2 km/hr

and going upstream = x-2 km/hr

dis /x+2 = 7⇒ dis = 7 (x+2)  (1 equation)

and dis / x-2 = 8 ⇒ dis = 8(x-2) (2 equation)

Now bring them together and apply

(1) =  (2)

7x + 14= 8x - 16  ⇒ x = 30 km/hr

and dis = 7(30+2) = 7 x 32 = 224 km