~Sandeep~ 12 years AGO

There has been so much of good information been shared on Perfect Square by everyone that we can write a encyclopedia article on it.....Admin Sir are you listening or do we need to elaborate more on this..

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Bimal 12 years AGO

This depends on the way you (or your source) define the term "square number." Some sources define a square number as any number that is the square of an integer. By this definition, zero is indeed a square number, because 0 = 0^2 and zero is an integer.

Others define a square number as any number that is the square of a
natural (or counting) number. The natural numbers are the set of all integers greater than or equal to one. Since zero is not considered a
natural number (and no other natural number squared equals zero), zero would not be considered a square number using this definition.

This second definition has more of a "geometric" interpretation.
Imagine measuring the area of a square that is n units on a side.
If n = 0, you don't really have a square to begin with - you have nothing. In ancient times mathematicians didn't count zero (or even
have a symbol for it) because they used numbers to represent physical measurements, and a physical object couldn't have a measurement of
zero.

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Inder 12 years AGO

@ vignesh,

If you read the question like that , then there is no possible answer which can be given to all the questions
as the statement says
'the total number of possible answers to all the questions is'.

Please think on practical lines .
Sometimes mathematicians have to ignore grammatical errors wherever possible.

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~Sandeep~ 12 years AGO

No I didn't say that Niru. :)
This is just true as per one of the definition.
I will say it is something which is not clear, some people consider it as Perfect Square and some do not.
Considering these facts the request was to avoid asking such questions as part of daily puzzle, and in this case marks should have been given to all who have answered 1 as well.

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niru 12 years AGO

@sandeep
ok sandeep i understood your explanation
then it is sure that zero is not a perfect square?

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Virendra Sihag 12 years AGO

Admin plz justify the 17th April question.
Zero is perfect square or not??

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Vignesh 12 years AGO

@ Dipin,

Thanks for reply. But one doubt.
In that question, they asked only possiile answers to all the questions. Didn't ask possible "combinations" of answers know.. So, answer would be

23 possible answers only know.

First four questions have 12 possible answers.(Each have 3 possible answer =3*4)
Next three questions have 06 possible answers.(Each have 2 possible answer =2*3)
Last one have 05 possible answers. (It have 5 possible answers)

So, (3*4)+(2*3)+(1*5) = 12+6+5 = 23 possible answers.


If I wrong means, please correct me..

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DIPIN 12 years AGO

@ Vignesh ,

If u mean this puzzle:

an examination paper consists of 8 questions of which 4 have 3 possible answers each,3 have 2 possible answers each and the remaining one question has 5 answers.the total number of possible answers to all the questions is

For 1st 4 qns, there are 3 possible answers.
So possible combinations for these 4 qns are 3^4.

Next 3 have 2 possible answers each .
possible combinations are 2^3.

remaining one question has 5 answers. means 5 options

so total possible combinations of answers are
(3^4)*(2^3)*5= 81*8*5 = 3240

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Vignesh 12 years AGO

@ All,

Please anybody explain the solution for puzzle (#M40008948) in the Placement Puzzle section.

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niru 12 years AGO

@sandeep
itself zero is in square if u write it alone

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mcj 12 years AGO

hi admin..how can you said that zero is perfect square..it is not a perfect square..please provide the reasonable solutions..thank you.

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~Sandeep~ 12 years AGO

O being a perfect square or not seems to be a debatable topic. I agree that lot of mathematicians consider it as Perfect Square but still there are considerable number of mathematician who don't consider 0 as perfect square.
As per the wiki link given by admin:
"The number m is a square number if and only if one can arrange m points in a square"
Again with this definition I don't know how to arrange 0 points in square.
Not sure why can't we have less controversial questions as part of daily puzzle?

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niru 12 years AGO

i also want to know that is a zero a perfect square ......
and if it is then there will be ans 2 have x=6 and x=0 ,,,,,,therefore the ans x=12 is i dont think right

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Balakumaran N.A 12 years AGO

only x= 6 is possible... 72 - 36 = 36 (perfect square)

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Balakumaran N.A 12 years AGO

Dear Admin,

I agree with Rakesh, Karthick babu... Please check on this...

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Karthick Babu 12 years AGO

Is it zero a perfect square? for 17th Apr puzzle

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manish kumar 12 years AGO

hey admin
i think the answer for the question which was asked today is 1
bcs 0 is not the square no. and its controversial
see this
http://mathforum.org/library/drmath/view/57171.html
plz give us points ... our answers are also correct.

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dineshv 12 years AGO

Hi admin

Can you please elaborate the 17/03 solution.
thanks in advance,waiting for your reply

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~Sandeep~ 12 years AGO

Great going Pragat :)

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Pargat Pal Singh 12 years AGO

Dear Admin,

Is anyone checking the solutions of placement puzzles?
These are still marked unsolved.

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Vignesh 12 years AGO

@ Govind

Not try to match. Try to beat(lead) Niru:-)

It also usefull for all know!! Thanks:)

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Vignesh 12 years AGO

@ Pargat

U doing a fabulous work in this site. Solving most of the puzzles which post by us.
Really great You are..

I wonder of You. Don't know how you able to solve all those.Really nice:-)

Congrats n keep rocking..

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bharathiraja 12 years AGO

super

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Govind 12 years AGO

Vignesh is also trying to match Niru.

Keep it up.

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niru 12 years AGO

thanks dipin,vignesh

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Vignesh 12 years AGO

Great Job Niru. Keep going. Congrats.

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DIPIN 12 years AGO

Congratulations, Niru.

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niru 12 years AGO

thanks for ur reply

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niru 12 years AGO

sir,sorry to say this but im the first who submitted 300 puzzles but acc. to ur prize rule u didnt response at all plz ......solve my query

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Trav 12 years AGO

In checking 1/x + 1/y = 1/205, I get 17 ordered pairs
x = -41820, y = 204
x = -8200, y = 200
...
x = 42230, y = 206
Must have missed something here

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Virendra Sihag 12 years AGO

I am talking about today's(4th April) question.
Why are you asking these type of lengthy question because they don't have any trick. Please ask some tricky questions.

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Vignesh 12 years AGO

@ Admin,

Thanks for awarding marks for me and all who chose option 4)26 on 02.04.2012 Puzzle:-):-)

Its Nice:-)

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~Sandeep~ 12 years AGO

I believe 0 is considered as non negative integer, Keeping my fingers crossed :).

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amritpal singh 12 years AGO

Oh No!

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Vignesh 12 years AGO

Oh No!

For Yesterday's(April 02, 2012) puzzle,

Find the next number
9, 16, 21, 24, ?

I thought answer will be 26(Option 4).
But it is 25(option 1.):-((

I thought that the given series was increasing by consecutive Prime Numbers(Reverse) from 7. (i.e, 7 5 3 2 1 like that)

9 +7 = 16
16 +5 = 21
21 +3 = 24

24 +2 = 26.

So sad:-(

K. Anyhow, Congrats for those who getting points:-)

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dhiresh 12 years AGO

Dear Admin,
I have an issue regarding awarding point system for today's puzzle system of yesterday(2nd april)
I submitted the right answer within 00:01:13,still i got 14 only and it is showing in last.
I think,it happened by automated point awarding system.
So, please keep updating your system and verify once before posting the result.You provide answer after hours then why such mistake?

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bharathiraja 12 years AGO

rtyre5y

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~Sandeep~ 12 years AGO

Welcome Trav...we are glad to have you here!
Admin will surely update you on your queries.

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Suman 12 years AGO

I fully agree with the logic given by Mr. Kewal.

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Suman 12 years AGO

I have earlier stated that due weightage should be given to time and investment but do not make it irrelevant by dividing each ratio by 0.6 and 0.4 to make it of equal importance(50:50) which is not correct in this case.

Your argument and answer holds good if weightage is 50% for investment and time.

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Suman 12 years AGO

Dear Admin,

As per qn.

60% weightage is given to investment and 40% weightage is given to time.

In that case
ratio of profit (for investment of 0, 1, 4, 5 lacs and time same( 3 hrs) for all)will be

(0*0.6 +3*0.4 ): (1*0.6+3*0.4):(4*0.6+3*0.4):(5*0.6+3*0.4) or 1.2 :1.8 :3.6 :4.2
or
2:3:6:7

Due weightage to time must be given as per qn.

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Trav 12 years AGO

From Texas:
This is a very enlightening web site. I also enjoy the fact that so far, I have not seen the rudeness that one finds on US sites. I'm 65 years old, an old Submarine Sailor, and way back when, we were taught to be polite to everyone. Refreshing indeed.

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Trav 12 years AGO

How do I make comments for answers to a puzzle that I submitted without using the solution function. For example, I modified the Houses in Oz question (base 6), and there was an answer in base 8 ( which was right for base 8).

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Trav 12 years AGO

Also, why does that verify tab open if I am verified.

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Trav 12 years AGO

I am not able to use the get file button to activate (it's dimmed) when I use the edit picture option. Help me Mr. Wizard.

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~Sandeep~ 12 years AGO

I totally agree with you Suman ... hope & wish that question would be more logical in coming days.

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Suman 12 years AGO

@Sandeep,

I am trying to make that point.
Due to this regular problem, I have not answered that qn.

One should take the discussion in right spirit.

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~Sandeep~ 12 years AGO

@ Suman - Many a times the logic behind the questions being asked here is beyond our understanding. Personally I feel mathematics problems are more appealing when they are logical, sensible and complex.

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Suman 12 years AGO

Thanks, PP Singh for telling fact of life.

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Suman 12 years AGO

Time is important but time of each person is equally important.

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Suman 12 years AGO

When everyone has worked for same hours per day, then ratio of profit distribution must be same as the ratio of investment of each person.

How the profit ratio can be changed from 1:13 to 1:7 when they worked for equal hrs per day?

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Pargat Pal Singh 12 years AGO

@ Suman,

When everyone thinks alike, No one thinks much.

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Suman 12 years AGO

Dear Admin,

If your logic is accepted , it will result in chaos in partenership plans of businessmen.
consider this example

If the four persons invested in the ratio of 1:5:9:13
and every one worked for 3 hours in a day,
then the profits will be distributed in the ratio of
(1+3):(5+3):(9+3):(13+3) or 4:8:12:16 or
1:2:3:4

when the fourth person has invested 13 times the amount invested by first persons and worked for same (3 ) hrs, but he will get profit 4 times only
which is not correct.

Pls think again.

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Amar 12 years AGO

DEar Admin,

Pls check yesterday puzzle sol.

effective investment ratio = 0.6:0.6:1.2:3.0 = 6:6:12:30 = 1:1:2:5
effective time ratio = 3.2:2.4:1.6:1.2 = 32:24:16:12 = 8:6:4:3

so according to the given condition profit ratio = 9:7:6:8

After multiplying ratios with 0.6 in first case and 0.4 in second case, you have divided the ratios by 0.6 and 0.4
to get ratios as 1:1:2:5 and 8:6:4:3 which are initial ratios of investment and working hours without any consideration of different priority/importance/weightage of 0.6:0.4.

so answer given is not correct.

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kewal 12 years AGO

I think solution given for yesterday puzzle is not correct.

This result is valid if
If output depends 50% on the investment and 50 % on work hours

and not

If output depends 60% on the investment and 40 % on work hours

which is given statement.

effective investment ratio = 0.6:0.6:1.2:3.0 =
effective time ratio = 3.2:2.4:1.6:1.2

In this case, profit ratio will be
3.8:3.0:2.8:4.2
or
19:15:14:21

which is none of given options.

As per your solution , you have given equal weightage to investment and working hours.

If you think my interpretation is wrong, then can anyone give the profit ratio when there is equal weightage for investment and working hours?

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~Sandeep~ 12 years AGO

Agree with Manish, Vigesh and Virendra.

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manish kumar 12 years AGO

improve the quality of questions .the question is asked on 29/3/2012 is the worst question i have ever seen stop asking non sense
questions plz.

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Anil 12 years AGO

this is very helpful site

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Virendra Sihag 12 years AGO

Please improve the level of the questions which asked everyday.

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~Sandeep~ 12 years AGO

@Atwal: Thanks for being like-minded.
On a funny note:
I have altogether started looking at the wheels in a different way now, they no longer revolve for me, they just skid so as to ensure a liner motion ;). Would suggest you to change your view too.
#ApologiesInAdvance

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Atwal 12 years AGO

I think Sandeep is right.

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srinivas 12 years AGO

it is good to all who are prepare for written exams....

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~Sandeep~ 12 years AGO

The question talks about speed of wheel (velocity and speed are different). Speed of wheel in general is measured by revolutions per minute . I am no longer bothered about points and all, but its expected that all the puzzles should be clear enough to arrive to a common solution by all members.

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~Sandeep~ 12 years AGO

Dear Admin,
Thanks for the response!

I will try to put my reasoning in simple words, as per the general notion speed of wheel can be measured in revolutions/second or revolutions per minute. Wikipedia link:
http://en.wikipedia.org/wiki/Specific_speed

Assuming speed of both wheels are V revolutions per minute and given that Radius of first wheel is 10cm & 2nd wheel is 20cm

Distance traveled by 1st wheel in one revolution = 2*pi*r = = 2*pi*10 cm = 20*pi cm

Number of revolution made by wheel 10 minutes =
10minute*V*revolutions/minute = 10V revolutions

Distance travelled by 1st wheel in 10 minutes = Number of revolution made by 1st wheel in 10 minutes * Distance traveled by 1st wheel in one revolution = 10V*20*Pi = 200V*Pi

In one revolution 2nd wheel will travel = 2*pi*R = 40*pi cm
Speed of 2nd Wheel is also V revolutions per minute

Assume Number of revolutions taken by 2nd wheel to travel 200*V*Pi cm distance is N
Hence N*2*pi*R = 200*V*Pi
putting R=20 we get N = 5V revolutions

Time taken by 2nd wheel to make 5V revolutions= Distance/ Speed = 5V Revolutions/ (V Revolutions/Minute) = 5 Minutes

Again it was not mentioned in the puzzle that speed is in meter per second.

Sandeep.

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~Sandeep~ 12 years AGO

Dear Admin,

Regarding Todays Puzzle of 14th March 2012 have following query confusion:
In general speed of wheel is mesaured in revolutions per minute or per second.
1st wheel's speed is v rpm and radius is R , the distance covered by it per minute = 2*Pi*R*v = S
Also 2nd wheel's speed is v rpm and radius is 2R , the distance covered by it it per minute = 2*Pi*2R*v =2S
Hence to cover S distance the larger wheel(2R Radius) would take half the time than the smaller wheel(R Radius).

Please clarify if my understanding or approach is incorrect.
Sandeep.

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vikash kumar 12 years AGO

multiplication rule for any no. multiple of 5 with any number.
first of all take examples like 25=5^2 ,125=5^3 ,625=5^4 etc now take the same power as 5 but this time on base 2 respectively.i.e for 25 it will be 2^2 ,for 125 it will be 2^3,for 625 it will be 2^4
now put same no of zeroes as the power of 5 on the given no.(whose multiplication with the multiple of 5 is required) and divide this no. by the calculated power value of 2 .now you will get the required answer.try it

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PANKAJ GUPTA 12 years AGO

please sent me divison short trick for math puspose

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Mike 12 years AGO

(a+b)4= a4+b4+4a3b+4ab3+2a2b2

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~Sandeep~ 12 years AGO

@Mario - ^ means power
Example 3^2 means 3 to the power of 2 = 9

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Mario Downer 12 years AGO

Can someone please tell me what is ^.

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Amar 12 years AGO

Happy holi to all.

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DIPIN 12 years AGO

Good observation, Jeevan..


I was lucky (along with other few lucky members ) that I missed that mistake and gave answer as per expectation of administrator.

But definitely answer should have been
none of these.

If it is a puzzle , that needs to be solved like a puzzle ( as given on site) not like general mathematical qn / solved example of a book with predetermined answer.

Hard luck for members taking the qn in 'right' spirit!

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Jeevan 12 years AGO

Pls check statement of yesterday puzzle

if x = 4/1+(4/1+(4/1+(4/1+(4 ........))))......upto infinite


then x^2 + x = ?


As per given statement , x= 4/1 + ...

\means x>4 , in that case
x^2+x

will be definitely greater than 20
.

so none of these.


If u mean that there is printing mistake in question as usual, then it is just murder of maths at this site.

In that case answer for previous puzzle needs rethinking if you do not know where to put the bracket for right qn..


The given answer as 4 is correct only for statement

if x = 4/(1+(4/(1+(4/(1+(4/(1+(4 ........))))00000......upto infinite
then x^2 + x = ?

and
not
if x = 4/1+(4/1+(4/1+(4/1+(4 ........))))......upto infinite
then x^2 + x = ?

Please check carefully .

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Vignesh 12 years AGO

Dear Admin,

There is lot of puzzles in queue which not verified by you, after submit correct solution by us. Please concern that all. It is useful for us. And it is also improvize the standard of our website by getting day to day response for our Solutions from You..

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~Sandeep~ 12 years AGO

@Pushpendra answer for the probability question is 53/80
Reason:
There is 2/5 chance that A is alive, so there's a 3/5 chance he's dead within 30 years. There's a 7/16 chance that B is alive, so there's a 9/16 chance he's dead within 30 years.
Thus Probability that both of them would be dead in 30 years = 3/5 x 9/16 = 27/80
Probability that at least one of these persons will be alive 30 years = 1-27/80 = 53/80

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Mahesh 12 years AGO

When actual time is 8PM, watch will display
(8:00- 0:(12/2)) = 7:54 PM

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Sulekha 12 years AGO

@ Jane,

For each hour an watch is going slow by 30 seconds. Now time is
8a.m.What will be the actual time at 8p.m.

What is ur qn please.

whether

What will be the display time when actual time is 8p.m

or
What will be the actual time when watch displays 8p.m

Pls confirm.

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Pargat Pal Singh 12 years AGO

Good job, sandeep.

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~Sandeep~ 12 years AGO

@ Vinod: Answer is 1.375
Reason:
Volume of cylinder = pi*H*R^2
Volume1/Volume2 = H1*R1^2/H2*R2^2
(R1/R2)^2 = (Volume1/Volume2)* (H2/H1)
=>R1/R2 = Square Root of [(Volume1/Volume2)* (H2/H1)]
Putting values as
Volume1 = 880, Volume2 = 640, H1= 72 & H2= 99
R1/R2= 1.375

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~Sandeep~ 12 years AGO

Also the winning order means that if a match is played between B and E and winning order is B>E, then B will win the match.

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~Sandeep~ 12 years AGO

@Aman: One question how did you conclude that "only" ABCD could reach final???
For example consider following two pools :
Pool 1 : ABCD
Pool 2 : EFGH
In the above case A and E will reach final.

Furthermore just considering the final two teams will not fetch you the right probability. We need to find out on possible combinations of teams in a pool using which A & B will reach finals. This will only happen when A and B are in different pools. Take following two cases.
Case:1 - A & B both reach finals
No. of ways to form two teams when A and B are in different pools (C anyways will not reach finals)= 6C3 = 20
Case:2: A reaches final but B doesn't
No. of ways to form two teams when A, B and C are in same pool (C will not reach finals in this case as well)= 5C1 = 5

In Case 2: A and B will not reach finals. Hence probability = 20/(20+5) = 4/5

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Aman 12 years AGO

Dear admin and friends,

The answer given for yesterday puzzle about 'Final match' is not correct.

It is already given that

There winning order is A>B>C>D>E>F>G>H.

In that case EFGH are in lower rank in both the pools in any possible arrangement.

Only ABCD can reach in semi final with all possible combinations .

As it is given that C has not reached in final,
Possible combinations for final are
AB
AD
BD.

Out of these three combinations, we ae interested in one combination i.e. AB.

Hence probability of final between A and b is 1/3.


I think administrator has forgotten the given condition

There winning order is A>B>C>D>E>F>G>H.


Please check and give your comments please.

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vivek singh 12 years AGO

i cracked my first campus TCS in November 2011...i convey my heartly thanks to all the members of m4maths community who directly or indirectly helped me to get through TCS......special thanks to admin for creating such a superb community

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Sushma 12 years AGO

In today's puzzle,
it is given that
There are 8 teams A, B, C, D, E, F, G, H. There winning order is A>B>C>D>E>F>G>H.

Can u make it clear whether this order is final or after knock out round ?

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ghanta komali 12 years AGO

why my solving time always shows hh:mm:ss:11:35:25
then how i get the points...........??

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Sushma 12 years AGO

@ Sunil,

The probability that a person A who is now 25 years old will not live for another 30 years is 1 - 2/5 = 3/5
The probability that the person B who is now 45 years old will not live for another 30 year is
1 - 7/16 = 9/16
The probability that none of these persons will be alive 30 years = (3/5)*(9/16) = 27/80
The probability that at least one of these persons will be alive 30 years = 1 - 27/80 = 53/80

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Vignesh 12 years AGO

@ All,
Please submit your puzzles in the placement puzzles section. Not in discussion board section.

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Dolly 12 years AGO

@ Pooja,

If you mean that watch is showing correct time at 8 AM,
and
you want correct time when watch shows 8 PM, then
after x correct hrs, displayed time is x-x/120 hrs

hence
x-x/120 =12
119x = 12*120
x= 12*120/119 = 12.1008 hrs or 12 hrs 6 mins approx

so correct time is 8:06 PM approx

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mangaldeep 12 years AGO

placement puzzle
Q id=#M40007848
Puzzle Status: Solved By »» Dolly
police Found G at the Murder site according to dolly g is the Judge
how??
it's wrong answer please check it

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