Brothers and sisters

Helen has as many brothers as sisters. Her brothers have twice as many sisters as brothers. How many brothers and sisters are in the family?

Final Answer:

b =  3
s =  4

Step-by-step explanation:

$$\begin{gathered} b=s-1 \\ 2(b-1)=s \\ 2(b-1)=b+1 \\ 2\cdot (b-1)=b+1 \\ b=3 \end{gathered}$$

$s=b+1=3+1=4$

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