CrazyEngineers Archive
Old, but evergreen and popular discussions on CrazyEngineers, presented to you in read-only mode.
@rengaraj • 07 Nov, 2009
Sir / madam,
My question is

A family I know has several children. Each boy in this family has as many sisters as brothers but each girl has twice as many brothers as sisters. How many brothers and sisters are there?

Advance Thanks,
R.Rengaraj
{SCE 34/2008/Pg 4 of 85}
{On this forum my 4th Question.}
@yadavundertaker mohit • 07 Nov, 2009 1 sister and 2 brothers.
@rengaraj • 08 Nov, 2009
yadavundertaker
1 sister and 2 brothers.
Sir,
Can it be 2 sister and 4 brother ???
Since they specified as many sisters.
Please Suggest.
R.Rengaraj
@yadavundertaker mohit • 08 Nov, 2009 what i think is that the question is not correct or i am unable to get it ...lets try it mathematically step by step

Let no. of brothers =x

Let no. of sisters =y

Acc. to Ist condition

x-1=y

Acc. to 2nd condition

y-1=2x

putting value of x in 2nd from Ist

y-1=2(y+1)

y=-3 which is not possible

then value of x is = -2 again it is not possible ...
@yadavundertaker mohit • 08 Nov, 2009 if the 2nd condition means each sister has double the sister as many as brother then we can solve this question

then 2nd condition becomes

2(y-1)= x

putting value of x from Ist equation to 2nd

2(y-1) =y+1

y= 3

then x = 4

No. of brothers =4

No. of sisters =3
@yadavundertaker mohit • 08 Nov, 2009
rengaraj
Sir,
Can it be 2 sister and 4 brother ???
Since they specified as many sisters.
Please Suggest.
R.Rengaraj

there cann't be 2 sisters if there are 4 brothers because according to the Ist each brother has same no. of sisters and brothers .And acc. to your answer each brother has 3 brothers and 2 sisters....
@Saandeep Sreerambatla • 09 Nov, 2009 The answer should be 3 sisters and 4 brothers.


Cond1 - Each brother has as many sisters as brothers.

So considering s1,s2,s3 and b1, b2,b3 and b4
Each of the b1 to b4 has 3 sisters and 3 brothers.

Cond2- Each girl has twice as many brothers as sisters

So now s1 has 2 sisters and 4 brothers.

similarly s2 and s3 also.

The answer is 3s and 4b..


Its not 1s and 2b because according to second condition there should be more than 1 girl.
@rengaraj • 09 Nov, 2009 Sir,
Excellent answer given.
But i didn't try mathematically, that's my mistake.
Thanks,
R.Rengaraj
@sharadha Shivakumar • 28 Oct, 2018

sir is it ok  to use co prime numbers

@Karshil Sheth • 14 Feb, 2020

I am guessing it randomly according to given situation.

So let be sisters be G and Brothers be B.

If There are 7 children, & G =2B, then for each girl there can be 4 brothers and 3 sisters.

so S1=B1,B2

 S2= B2,B3

S3=B3,B4.

So I guess answer is :3 sisters and 4 brothers.

@Divisha Madupalli • 14 Feb, 2020

no of boys is higher than girls by 1

 it is only possible when she has 2 sisters and 4 bothers.

Answer is: There are 4 sons and 3 daughters.

Related Posts

@Kaustubh Katdare · Oct 14, 2015

Samsung Z3 has been launched in India with a price tag of Rs. 8490. The Tizen powered phone offers a 5" S-AMOLED HD display, 1GB of RAM and 8GB of...

@Kaustubh Katdare · Apr 2, 2014

I had an opportunity to watch the 4K Ultra-HDTV at a Sony showroom and was fairly impressed by the quality of the display. Samsung recently announced 4K Monitors in the...

@PraveenKumar Purushothaman · Jun 26, 2017

Adding to Facebook, Twitter, now WhatsApp is picking up in "Social Media" although it is not a social media. Now, how many of you know that you can directly send...

@madhulika19 · Dec 23, 2013

there are 60 seats in c-dac(pune+noida) for pgd-gi course.. and my rank in section A is 64 what are my chances? which c-dac institute is best for pgd-gi(geoinformatics) course, pune...

@Kaustubh Katdare · Jan 30, 2014

It's no brainer that accumulation of dust on the surface of solar panels, also called 'soiling', is one of the main reasons that affects the efficiency of solar power plants....