Question

a motorboat whose speed is 18 km per hour in still water takes 1 hour more to go 24 km upstream then to return downstream to the same spot find the speed of the stream

Answer 1

Let speed of stream be x km/hr

Speed of boat in still water= 18km/hr

Then, speed of boat to go upstream= 18-x km/hr

And,speed of boat to come down stream= 18+x km/hr

As we know, time=distance÷speed

Given “boat takes 1 hour more to go upstream”,

Then, equation is

24÷18-x - 24÷18+x=1

so,

the speed would be

6kmph

Answer 2

Answer:

6 km / Hr

Step-by-step explanation:

Stream Speed = S km / Hr

Distance = D km

Time Upstream = D / (18-S)  Hr

Time Downstream = D/ (18+S) Hr

{D / (18-S)}  - {D / (18+S)}  = 1

Solving this we get

S²+2DS-18² = 0

D = 24 km

then S² + 48S - 324 = 0

(S+54)(S-6)= 0

S = 6 as S can not be negative