Pratik takes 8 hours to travel 36 km downstream and return to the same spot the speed of boat in still water is 12 kilometre per hour find the speed of water current

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Filo · Accepted Answer

Let the speed of the current be x km/hr.Pratik goes 36 km downstream. ∴ Distance covered by the Pratik in Downstream =36 km.Speed of the Pratik in downstream =(12+x) km/hr.∴ Time taken =(12+x)36​Now, He also returned to the same spot.∴ Distance covered in upstream =36 km.Speed of the Pratik in upstream =(12−x) km/hr. ∴ Time taken =(12−x)36​Now,  Time taken in upstream + Time taken in downstream =8 hrs.∴(12−x)36​+(12+x)36​=8⇒ 36(12+x)+36(12−x)=8(12+x)(12−x)⇒36(12+x+12−x)=8(144−12x+12x−x2)⇒36×24=8(144−x2)⇒ 36× 3=144−x2∴x2=144−108∴x=36​⇒x=+6 or −6−6 cannot be possible.∴ Speed of the current is 6 km/hr.

Question Text	Pratik takes $8$ hours to travel $36$ km downstream and return to the same spot the speed of boat in still water is $12$ kilometre per hour find the speed of water current
Answer Type	Text solution:1
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Pratik takes $8$ hours to travel $36$ km downstream and return to the same spot the speed of boat in still water is $12$ kilometre per hour find the speed of water current

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