A boat covers a certain distance downstream in 4 hours but takes 6 hours to return upstream to the starting point. if the speed of the stream be 3 km/hr, find the speed of the boat in still water
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Let the speed of the water in still water = x
Given that speed of the stream = 3 kmph
Speed downstream = (x+3) kmph
Speed upstream = (x-3) kmph
He travels a certain distance downstream in 4 hour and come back in 6 hour.
ie, distance travelled downstream in 4 hour = distance travelled upstream in 6 hour
since distance = speed × time, we have
(x+3)4=(x−3)6
=> (x + 3)2 = (x - 3)3
=> 2x + 6 = 3x - 9
=> x = 6+9 = 15 kmph
Given that speed of the stream = 3 kmph
Speed downstream = (x+3) kmph
Speed upstream = (x-3) kmph
He travels a certain distance downstream in 4 hour and come back in 6 hour.
ie, distance travelled downstream in 4 hour = distance travelled upstream in 6 hour
since distance = speed × time, we have
(x+3)4=(x−3)6
=> (x + 3)2 = (x - 3)3
=> 2x + 6 = 3x - 9
=> x = 6+9 = 15 kmph
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