SOLUTION: A boy said I have as many brothers as i have sisters.Then his sister said i have double the number of brothers as i have sistes.Find the number of brothers and sisters.

Algebra.Com
Question 395635: A boy said I have as many brothers as i have sisters.Then his sister said i have double the number of brothers as i have sistes.Find the number of brothers and sisters.
Found 2 solutions by jrfrunner, richard1234:
Answer by jrfrunner(365)   (Show Source): You can put this solution on YOUR website!
let B=total boys, G=total girls
boy's criteria: equal number of brothers and sisters
girl's criteria: twice as many brothers as sisters
-
if B=1 and G=1, this does not satify the conditions
if B=2 and G=1 satisfies boy's criteria but not sister's
if B=2 and G=2 does not satify the boy's criteria but satisfies sister's
if B=3 and G=2 satisfies boy's criteria but not sister's
if B=3 and G=3 niether condition satisfied
if B=4 and G=2 neither condition satisfied
if B=4 and G=3 satisfies both conditions

Answer by richard1234(7193)   (Show Source): You can put this solution on YOUR website!
The boy says that he has x brothers and x sisters, so there are x+1 boys and x girls. The sister says that she has 2y brothers and y sisters, so 2y boys and y+1 girls. These numbers differ by 1, so

2y = x+1
y+1 = x

Solving, we get y = 2, so there are 3 girls and 4 boys.

RELATED QUESTIONS

A boy said I have as many brothers as i have sisters.Then his sister said i have double... (answered by Edwin McCravy)
A boy says "I have the same number of sisters as I have brothers". His sister says "I... (answered by htmentor,Edwin McCravy)
My daughter has many sisters. She has as many sisters as she has brothers. Each of her... (answered by ankor@dixie-net.com)
My daughter has many sisters. She has as many sisters as she has brothers. Each of her... (answered by solver91311)
A son in the family says I have sisters twice as many as brothers. A daughter in the same (answered by josgarithmetic)
I have two more sisters than brothers. Each of my sisters has two more sisters than... (answered by ikleyn)
Each of my daughters has as many brothers as sisters, but each of my sons has three times (answered by josmiceli)
Phil & phyllis are siblings. phyllis has twice as many brothers as she has... (answered by psbhowmick)
If I have 2 more sisters then brothers and each of my sisters also has 2 more sisters... (answered by Shin123,ikleyn,Edwin McCravy)