Question

a motor boat whose speed is 18 km/hr in still water take 1 hr more to go 24 km upstream than to return downstream to the same spot. find the speed of the stream ​

Answer 1

Answer: v= 4200 m/s

Step-by-step explanation:

u= 18 km/h = 5 m/s

t= 1 hrs=60 sec

s= 24km = 2400m

s=ut+1/2at

2400=5*60+1/2 a * 60

2400=300+ a * 30

2400-300= a* 30

2100/30=a

a=70 m/s

V=U+AT

V=5+70*60

V=4200 M/S

Answer 2

Answer:

Let the speed of stream be x km / hr

For upstream = ( 18 - x ) km / hr

For downstream = ( 18 + x ) km / hr

A.T.Q.

24 / 18 - x - 24 / 18 + x = 1

48 x = 324 - x²

x² + 48 x - 324 = 0

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

x = - 54 or x = 6

Since speed can't be negative .

Therefore , speed of the stream is 6 km / hr .