Question

a boat travels 30 km upstream in the same amount of time it takes to travel 60 km downstream in the same river with the speed of the river is 4 kilometre per hour find the speed of the boat in still water​

Answer 1

Step-by-step explanation:

let,the speed of boat in still water is=x km/hr

then the relative velocity in upstream is=(x-4)&

downstream velocity=(x+4)

we know,

D/V=T [D=Distance,V=Velocity,T=time]

hence, for upstream

T=30/(x-4)

for downstream

T=60/(x+4)

according to question, time was same

then,,

30/(x-4)=60/(x+4)

2x-4=x+4

x=8