600, find production cost of one 7* Pratik takes 8 hours to travel 36 km downstream and return to the same spot. TH speed of boat in still water is 12 km. per hour. Find the speed of water current. Pintu takes a days more than those of Nishu to complete certain work. If they won
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Answers
Let the Speed of the Water Current be x km/hr.
→In Case of the Downstream,←
Distance Covered by the Boat in Downstream = 36 km.
Speed of the Boat in Downstream = (12 + x) km/hr.
Using the Formula,
→ Speed = Distance/Time
→ Time(T1) = 36/(12 = x) hrs.
→In case of Upstream,←
Distance covered by the Boat in Upstream = 36 km.
Speed of the Boat in Upstream = ( 12 - x) km/hr.
Thus, Time(T2) = 36/(12 - x) hrs.
⇒According to the Question,
T1 + T2 = 8 hrs.
36/(12 + x) + 36/(12 - x) = 8
36[ 12 - x + 12 + x] = 8(12 - x)(12 + x)
36 × 24 = 8 [144 - x²]
⇒ 108 = 144 - x²
x² = 144 - 108
x² = 36
x = √36
x = +6 or x = -6
Since x = -6 cannot be possible because speed of the current cannot be negative.
⇔Thus, Speed of the Water Current is 6 km/hr.⇔
I anticipate it will help u.
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−x
2
)
⇒36×24=8(144−x
2
)
⇒36×3=144−x
2
∴x
2
=144−108
∴x=
36
⇒x=+6 or −6
−6 cannot be possible.
∴ Speed of the current is 6 km/hr.