a motor boat whose speed is 18 km/h in still water takes 1 hour more
get 24km upstream than to return downstream to the same

2 thoughts on “a motor boat whose speed is 18 km/h in still water takes 1 hour more<br />get 24km upstream than to return downstream to the same”

1. Answer:

   6 km\h

   Step-by-step explanation:

   speed of the stream is 6km\h

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2. Answer:

   6km/hr

   Step-by-step explanation:

   Given parameters:

   The speed of the motorboat in still water =18 kmph

   Let us consider

   The speed of the stream = s

   Speed of boat upstream = Speed of a boat in still water – the speed of a stream

   Speed of boat upstream = 18 – s

   Speed of boat downstream = Speed of a boat in still water + speed of a stream

   Speed of boat downstream = 18 + s

   Time is taken for upstream = Time taken to cover downstream + 1

   time =distance/speed

   \frac{Distance_{upstream}}{Speed_{upstream}} = \frac{Distance_{downstream}}{Speed_{downstream}} + 1

   24/ (18 – s) = [24/(18 + s)] + 1

   24(18+s) = 24(18−s) + (18−s)(18+s)

   s2 + 48s − 324 = 0

   s2 + 54s − 6s − 324 = 0

   (s+54)(s−6) = 0

   s = 6,−54 but s ≠−54

   Since the speed of steam cannot be negative.

   ∴ s = 6km/hr

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