age-based word problem Peter's age is three years more than three times his son's age. After three years, Peter's age will be ten years more than twice his son's age. What is Peter's present age? 
I have tried to put this into algebra, but not sure if correct? 
$x =$ Peter's son's age  
$p =$ Peter's age 
\begin{align*}
3x + 3 & = p\\ 
10 + 2x & = 3 
\end{align*}

In fact $x$ and $p$ denote Peter's son's and Peter's age at this moment in time respectively:
$x=$ Peter's son's age right now,
$p=$ Peter's age right now.
So when we talk about peter's son's or his age in three years from now, we are talking about $x+3$ and $p+3$. Therefore we have these equations:
$$\left\{\begin{array}{}p=3x+3\\p+3=10+2(x+3)\end{array}\right.$$
