Latest Capgemini Aptitude Question SOLUTION: A speedboat whose speed is 15 kmph in still water goes 30 kmph downstream and comes back in a total of 4hrs 30min. What is the speed of the stream in kmph?

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A speedboat whose speed is 15 kmph in still water goes 30 kmph downstream and comes back in a total of 4hrs 30min. What is the speed of the stream in kmph?

Asked In Capgemini bhojraj dhakate (9 years ago)

Unsolved Read Solution (17)

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Read Solution (17) :

bhagyashree parija  (9 years ago)

sorry
the answer is 5kmph
solution:-
Let the speed of the stream be x km/hr. Then,

Speed downstream = (15 + x) km/hr,
Speed upstream = (15 - x) km/ph
30/(15+x)+30/(15-x)=4.5
solve for x
x=5kmph



x = 5 km/hr.

Is this solution Helpfull? Yes (20) | No (3)  

Gouri Padhy  (9 years ago)

but 30kmph is not the distance

Is this solution Helpfull? Yes (14) | No (5)  

roja  (9 years ago)

i think its 15 km/hr... bcoz
ds=boatspeed + streamspeed (let stream speed = x)
=> 30=15 + x
=> x = 15 km / hr

Is this solution Helpfull? Yes (12) | No (7)  

Narasapu Hari prasad  (9 years ago)

Ans is 5 kmph
Sorry speed of the strem is 5kmph
let x is apeed of stream
30/(15+x)+30/(15-x)=4.5
solve for x you will get x=5

Is this solution Helpfull? Yes (9) | No (2)  

bhagyashree parija  (9 years ago)

let the speed of boat in still water=x kmph
speed of stream= y kmph
down stream=ds
ds=x+y
y=ds-x=30-15=15kmph

Is this solution Helpfull? Yes (4) | No (7)  

debasish Majumder  (9 years ago)

ans is 5kmph..
as we know the formula,speed downstream=(speed in still water+speed of stream)

now,let speed of stream be x..

so,by the given formula we get

30=(15+x)..

again in the given question the boat comes back,so 30=(15-x)

Therefore,by the given 2equations,

30/(15+x) + 30/(15-x)=4.5(time given)

solving we see,x=5


Hence the speed of the stream is 5kmph..

Is this solution Helpfull? Yes (4) | No   

Narasapu Hari prasad  (9 years ago)

ans is 20 km/p
the speed of water is 20 km per hour

Is this solution Helpfull? Yes (2) | No (9)  

mac  (9 years ago)

In this question , it should be "A speedboat whose speed is 15 kmph in still water goes 30 km downstream " and not 30kmph !!!

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CHANDRAN  (9 years ago)

hear distance is not 30 km

I think answer is 15 kmph because in downstream boat speed= speed in still water + stream speed
So, 15 + stream speed = 30 =====.> strem speed = 15 kmph

Is this solution Helpfull? Yes (1) | No (1)  

shubhankar barman  (9 years ago)

Let the speed of the stream be x km/hr. Then,

Speed downstream = (15 + x) km/hr,

Speed upstream = (15 - x) km/hr.

30 + 30 = 4 1
(15 + x) (15 - x) 2
900 = 9
225 - x2 2
9x2 = 225

x2 = 25

x = 5 km/hr.

****note: 30 km downstream means it goes 30 km.It is distance

Is this solution Helpfull? Yes (1) | No (3)  

jamini mohan gogoi  (9 years ago)

if 30kmph is the combined speed then the answer will be 30-15=15
but if it is distance 30 km then answer is 5kmph

Is this solution Helpfull? Yes (1) | No (1)  

hp maity  (9 years ago)

the question is given wrong
A speedboat whose speed is 15 kmph in still water goes 30 km downstream and comes back in a total of 4hrs 30min. What is the speed of the stream in kmph
that is the exact ques.
and ans is 5 km.
A speedboat whose speed is 15 kmph in still water goes 30 kmph downstream and comes back in a total of 4hrs 30min. What is the speed of the stream in kmph

Is this solution Helpfull? Yes (1) | No (1)  

kamlesh kumar mehta  (7 years ago)

Let the speed of the stream be x km/hr. Then,

Speed downstream = (15 + x) km/hr,

Speed upstream = (15 - x) km/hr.

30 + 30 = 4 1
(15 + x) (15 - x) 2
900 = 9
225 - x2 2
9x2 = 225

x2 = 25

x = 5 km/hr.

Is this solution Helpfull? Yes (1) | No (1)  

KONA VENKAT  (9 years ago)

speed of stream= downstream speed - speed of the boat in still water
= 30-15=15kmph

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M.Bhuvaneswari  (9 years ago)

ans 15kmph.
speed of boat=15 kmph
downstream= 30 kmph
downstream= speed of boat+ speed of stream
30=15+speed of stream
speed of stream = 15 kmph (i think its correct)

Is this solution Helpfull? Yes | No (1)  

rakesh bhagat  (9 years ago)

speed of stream is 3kmph

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Ajith Raj  (7 years ago)

the question is wrong
at the place of 30 kmph it should be 30 km only ...
than correct answer is 5

i ask u one question those who are telling answer as 15
if the speed of boat as well as the steam both become 15 how it is possible to a boat to be come back . (it only go by a speed of 15+15=30 but while returning time speed will be 15-15= 0 so not possible to come back )

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