Question

A man rows 30 km downstream and 18km upstream .taking 5 hours time each.what is the velocity of the current
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Answer 1

Step-by-step explanation:

6km/hr ,3.6km/hr or 4.75km/hr

as

velocity of downstream=30/5=6km/hr

velocity of upstream=18/5=3.6km/hr

velocity of still water=6+3.6/2=9.6/2=4.75km/hr

it may help you

Answer 2

Answer:

1.2km/hr

Step-by-step explanation:

Let man's rowing speed be "x" and the current speed be "y".

first method

When rowing downstream, the current speed adds to the man's rowing speed. When rowing upstream, the current speed acts against the man's rowing speed.

distance=speed×time

so while moving downstream,

30=[x+y] × 5. (eqn-1)

while moving upstream

18=[x-y] × 5. (eqn-2)

adding eqn 1 &2 we get

48= 10x

so x= 4.8

putting this value of x in eithr eqn 1 or 2, we get the current's speed. y= 1.2 Km/hr

second method

speed of current = 1/2 ( downstream speed - upstream speed )

speed of current = 1/2 ( downstream speed - upstream speed )= 1/2 ( 30/5 - 18/5) = 1/2 ( 6- 3.6) = 1.2 km/h