Answer:
Barry has 15 dollars, Sherry 35 dollars and Perry 70 dollars.
Step-by-step explanation:
Let's start by setting Sherry's cash as a variable named x, Barry's cash named as y and Perry's cash named as z.
The 3 children together have 120$, meaning that the following equation is true:
If Barry (y) has 20$ less than Sherry (x), then we can conclude, that:
If Perry (z) has 2 times the amount of money Sherry (x) has, then we can conclude, that:
If we replace all the y and z variable in the first equation with what we just made, we get a way easier equation than before:
We can easily remove the brackets and go on to solving the equation, giving us x, which is equal to how much money Sherry has:
So, Sherry has 35$. Since Barry has 20$ less than 35$, we can conclude, that:
Barry has 15$.
If Perry has 2 times the amount Sherry has, then we can conclude, that:
Perry has 70$.