Question 206088: 4. Rita rows 12 km upstream and 12 km downstream in 3 hours. The speed of her boat in still water is 9 km/hr. Find the speed of the stream. Answer by anantha(86) (Show Source):
You can put this solution on YOUR website! sol:
speed=distance/time
according to the question
speed of upstream=distance/time=12/3=4km/hr
according to the question speed of boat in still water=9 km/hr
let speed of stream= x km/hr
now speed of upstream=speed of boat in still water-speed of stream
substitute above values in this formula ,we get
4km/hr=9 km/hr-x
transposing x from R.H.S to L.H.S and 4 from L.H.S to R.H.S
x=9 km/hr-4 km/hr= 5km/hr
speed of stream=5 km/hr
check:speed of upstream=4km/hr
speed of upstream=speed of boat in still water-speed of stream
=9 km/hr- 5 km/hr=4 km/hr
L.H.S= R.H.S (as requried)
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