A boatman goes 5 km against the current of the stream in 3 hour and goes 4.5 kms along the current i

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06 Jul 2017 Speed and Time

A boatman goes 5 km against the current of the stream in 3 hour and goes 4.5 kms along the current in 30 minutes. How long will it take to go 16 km in stationary water?

OPtion

1) 3 hours 33 minutes
2) 3.23 hours
3) 3 hours 30 minutes
4) 3 Hours 0 minutes
5) 3 hours 15 minutes
6) 3.03 hours
7) 3 hours 20 minutes
8) 3 hours 25 minutes
9) 3.5 hours
10)None of these

Solution

Speed (upstream) =5/3 km/hr
Speed (downstream)=4.5/0.5= 9 km/hr

Speed in still water = 1/2 (9+5/3) = 16/3 km/hr

Time taken in stationary water to go 16 KM = 16/16/3 = 3 hr

Option 4)

Correct Option: 4 Best Solution (17)

G.S.Kantharao   7 years AGO

Up strem relative speed=(x-y)kmph
Time taken=3hrs
Distance = 3(X-Y)= 5
3X-3Y=5
Downward Relative Speed= (X+Y)kmph
Time taken 1/2hr
(X+Y)*1/2= 4.5
(X+Y)=9
Simplyfing 6X=32
X=16/3
In still water time taken to travel 16km= 16/(16/3)=3hrs. Hence the right option is 4.👍

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SAYAN CHATTERJEE   7 years AGO

let, speed at stationary water= x and speed of boat= y
so, 5/(x-y)= 3,
4.5/(x+y)=0.5
on solving, x=16/3
so, time reqd to travel a distance of 16 km = 16/(16/3)
= 3 hours.
Option 4.

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tumati koushik   7 years AGO

Stream velocity =s
Boat velocity =b
S+b=4.5x2=9
B-S=5/3
B=16/3
So 16 km in 3 hours

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AYAN PAUL   7 years AGO

Speed of boat against the current is = 5/3 Km/hr
Speed of boat with the current is = 9 Km/hr
So speed of boat in stationary water will be = 16/3 Km / hr
So the time required to travel 16 km will be = 16*3/16 = 3 hr.

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ganesh chemanchula   7 years AGO

Sped in Upstream is 5/3
Speed in downstream (4.5/(1/2))
Speed in still water is 1/2(speed in upstream + speed in downstream)=1/2(32/3)=(32/6)
Time take to cover 16 kms in still water is 16/(32/6)=96/32=3 hours
So option 4.

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Prerna   7 years AGO

If B is speed of boat in stationary water and C is speed of current, then
B+C= 4.5*2= 9 km/hr
B-C= 5/3
2B= 32/3 km/hr
B=16/3 km/hr
so time taken by boat to travel 16 km in stationary water = 3 hrs

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Mukund Manohar   7 years AGO

Speed Upstream = 5/3 km/h
Speed Downstream = 4.5/(30/60) = 9 km/hr
Speed in still water = 1/2(5/3 + 9) = 16/3 km/hr
Time taken to travel 16 km in still water = 16/(16/3) = 3 hrs

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Tavva Deepthi   7 years AGO

upstream =5/3=1.666666667km/hr
downstream=4.5/(30/60)=9km/hr
speed in still water =1/2*(1.666666667)=5.333333334km/hr
time taken on stationary water to go 16km=16/5.333333334=3hours0minutes

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Saptarsy Chakraborty   7 years AGO

Speed of boat-speed of stream=5/3 km/hr ----(1)
Speed of Boat+Speed of stream = 4.5/30 km/min
= 4.5/0.5 km/hr
= 9 km/hr. -------(2)
(2) - (1) OR (2) minus (1),
2*speed of boat=32/3. Therefore Sp of boat= 16/3 km/hr.

So, Time taken by boat in still water= dist. /speed
=16/(16/3)
=3 hours.

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Pallavolu vaasavi   7 years AGO

v-u=5/180
v-u=4.5/30
by solving the above equations we get v=4/45
v=d/t
4/45=16/t
therefore t=180min
t=3hrs 0min

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Shoieb   7 years AGO

b-s=5/3
b+s=9
we get b=16/3
for 16km it will take 16÷16/3 = 3

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Gnana Shankar   7 years AGO

The speed of the batman is 16/3 kmph and the speed of current is 11/3 kmph. So in a stationary water he goes 16 km in 3 hours without the help of current speed but only by his speed.

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Mathangi   7 years AGO

Going against the stream means upstream. so the upstream speed is (5/3) km/hr. And going along the stream means downstream, and the downstream speed is (4.5/(1/2)), i.e 4.5*2=9 km/hr. (30 minutes is converted into 1/2 hours). now speed in still water is (upstream+downstream speeds)/2. Hence ((9+(5/3))/2)= 16/3 km/hr. The distance is 16 km. So time is distance/speed which will be equal to 16/(16/3)= 3 hours.

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Sri Harshitha   7 years AGO

upward stream
for 5km he takes 3 hours(against so upward stream)
for 1 hour 1.6666 km
downard stream
(4.5*60)/30=9
speed in still water=1/2*(9+1.6666)=5.3333
required time=16/5.3333=3 hours 0 minutes

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saima haque   7 years AGO

Speed in stationary water=(5/3 +4.5×2/3)/2=32/6.
Now time taken for 16km =16×6/32=3 hr

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palak Jain   7 years AGO

speed of downstream a=4.5*60/30=2km/hr
speed of upstream b=5/3 km/hr
speed of boat u=(a+b)/2=32/6 km/hr
time=16*6/32=3 hr

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Sirra surresh   7 years AGO

5000/180=250/9 so 250mt in 9 min in upstream.1350 Mt in 9min I'm down stream so the average is800 Mt in9min still water
So 16000mt in180 min

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