\documentclass[11pt,letterpaper]{report}
\usepackage[latin1]{inputenc}
\usepackage[spanish]{babel}
\usepackage{amsmath}
\usepackage{amsfonts}
\usepackage{amssymb}
\usepackage{graphicx}
\usepackage[left=3.17cm,right=3.17cm,top=2.54cm,bottom=2.54cm]{geometry}
\usepackage{tabularx}
\author{Leonardo Mora Castro}
\begin{document}
\begin{tabularx}{\linewidth}{>{\raggedleft\arraybackslash}X}
\begin{tabularx}{\linewidth}{XX}
bub & bjbh
\end{tabularx}
\end{tabularx}
\end{document}