Question

a boat takes 5hrs to go 300 km downstream. if it takes the same time to go 15km upstream calculate the speed of the boat in still water and speed of the stream ...
pls solve this

Answer 1

Answer:

let the speed of boat = x

let the speed of stream = y

distance in downstream  =300km ;   distance in upstream =15km

time in both cases=5hrs

speed=distance/time

downstream

x+y= 300/5                    

∴x+y=60        ......(1)

upstream

x+y=15/5

∴x-y=3           .....(2)

now solving (1) and (2)

x+y=60

x-y=3

           

2y=63

y=31.5

putting value of y in equation (2)

x-y=3

x-31.5=3

x=3=31.5

x=34.5

hence,

the speed of boat = x = 34.5

the speed of stream = y = 31.5