In my family, the girls have twice as many sisters as brothers and the boys have one-third as many brothers as sisters

Question

In my family, the girls have twice as many sisters as brothers and the boys have one-third as many brothers as sisters? 

Answer 1

9 girls & 4 boys in the family

each girl has 8 sisters and 4 brothers or twice as many sisters as brothers

each boy has 3 brothers and 9 sisters or 1/3 as many brothers as sisters

Two equations two unknowns. Let G= number of girls, B=number of boys

G-1 = the number of sisters a girl has

B-1 = the number of brothers a boy has

G-1=2B

B-1=(1/3)G

G=2B+1

B-1 = (2B+1)/3

3B-3 = 2B+1

B=1+3=4

G=2B+1 =2(4)+1=9

another solution is zero children, as 0 sisters is twice 0 brothers

and 0 brothers is 1/3 of 0 sisters.

S=2B

for girls

for boys

B=S/3

S=3B

2B=3B

B=0, S=0