## Sisters and Brothers

My daughter has as many sisters as she has brothers. Each of her brothers has twice as many sisters as brothers. How many sons and daughters do I have?

Four daughters and three sons. Each daughter has 3 sisters and 3 brothers, and each brother has 2 brothers and 4 sisters.

To figure it out mathematically, you could use the following two equations where G = the number of girls and B = the number of boys:
G – 1 = B
2(B – 1) = G

Solving for G gives you 4 and plugging that in to G – 1 = B gives you a B of 3.

Posted in Brain Teasers

10 Comments on "Sisters and Brothers"

Adithya says
February 21, 2016 @ 05:39

4

Chloe says
February 22, 2016 @ 06:46

3boys & 4girls ??? ?

sakshi singh says
June 22, 2016 @ 06:57

Answer is 7

Mhd mhd says
July 11, 2016 @ 12:15

answer is :
2 daughters & 1 son

Dinesh Bhimsaria says
October 21, 2016 @ 03:08

One son and two daughters.

GraceyCakes says
November 23, 2016 @ 10:43

It is 4 daughters and 3 sons. It cannot be 2 daughters and 1 son because the son has to have twice as many sisters as brothers. 2*0(he has no brothers) is 0, therefore this will not work. Whereas with 4 daughters and 3 sons, one daughter will have the same amount of sisters and brothers (3), and one son will have twice as many sisters as brothers. 2*2(he has 2 brothers) is 4, the correct amount of sisters he has. Therefore, the correct amount is 4 daughters and 3 sons.

ZW says
July 25, 2018 @ 20:49

Couldn’t the answer also be 2 daughters and 1 brother?

My daughter has as many sisters as she has brothers.

(If it was 2 daughters, 1 brother, still true— making “my daughter” having 1 sister, 1 brother)

Each of her brothers has twice as many sisters as brothers. How many sons and daughters do I have?

(If it was 2 daughters, 1 brother, still true bc her brother would have 2 sisters and 0 brothers making it 2x as many sisters as brothers)

ZW says
July 25, 2018 @ 20:51

It could be 2 daughters 1 son and just because 0x2=0 that’s not the question. If I’ve been skydiving twice and you’ve never been, I’ve still been skydiving twice as many times as you….

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