Large family

I have as many brothers as sisters and each my brother has twice as many sisters as brothers. How many children do parents have?

Result

n =  7

Solution:

n = m+z
m -1 = z
2(z - 1) = m

m-n+z = 0
m-z = 1
m-2z = -2

m = 4
n = 7
z = 3

Calculated by our linear equations calculator.

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