\documentclass[letter]{article}
\usepackage{amsmath}
\usepackage{amssymb}
\usepackage[margin=1in]{geometry}

\newenvironment{problem}[1]
{
	
	\noindent \textbf{Problem #1} \itshape 
}{
	\vspace{10pt}
	
}
\newenvironment{solution}
{
	\noindent \textbf{Solution:} 
}{
	\vspace{20pt}
	\hrule
	\vspace{20pt}
}


\author{The Author's Name}
\title{Homework Template}
\date{\today}

\begin{document}
	
	\maketitle
	
	\begin{problem}{number goes here}
		Problem Statement
	\end{problem}
	\begin{solution}
		blah blah blah
	\end{solution}
	
	
	\begin{problem}{number goes here}
		Problem Statement
	\end{problem}
	\begin{solution}
		blah blah blah
	\end{solution}
	
	
\end{document}