Answer
The girl has $1000$, the mother has $2000$, the boy has $4000$.
Work Step by Step
Let $x$ denote the amount of money the girl has. Then $2x$ denotes the amount of money the mother has and $4x$ denotes the amount of money the boy has. We know that in total they have $14000$, thus $x+2x+4x=14000\\7x=14000\\7x/7=14000/7\\x=2000.$
Thus the girl has $1000$, the mother has $2000$, the boy has $4000$.
