a boat takes 2 hrs to go 4 km down the stream and return in 4 hrs find the speed of the boat in still water and speed of the stream
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Lets speed of boat = x km/hr
and speed of current = y km/hr
So while going upstream speed of man = x-y km/hr
and while going downstream = x+y km/hr
A/Q : 4/x+y = 2 ⇒ 2x + 2y = 4 ⇒ x+y = 2 ⇒ y = 2-x ..........(1)
And 4 /x-y = 4 ⇒ x-y = 1 from (1)
x-(2-x) = 1 ⇒ 2x - 2 = 1 ⇒ x = 3/2 and so y = 1/2
Hence speed of boat = 1.5 km/hr (in still water)
speed of current = 0.5 km/hr
Hope this helps.
and speed of current = y km/hr
So while going upstream speed of man = x-y km/hr
and while going downstream = x+y km/hr
A/Q : 4/x+y = 2 ⇒ 2x + 2y = 4 ⇒ x+y = 2 ⇒ y = 2-x ..........(1)
And 4 /x-y = 4 ⇒ x-y = 1 from (1)
x-(2-x) = 1 ⇒ 2x - 2 = 1 ⇒ x = 3/2 and so y = 1/2
Hence speed of boat = 1.5 km/hr (in still water)
speed of current = 0.5 km/hr
Hope this helps.
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