1985 AJHSME Problem 19

If the length and width of a rectangle are each increased by 10\%, then the perimeter of the rectangle is increased by

\textbf{(A)}\ 1\% \qquad \textbf{(B)}\ 10\% \qquad \textbf{(C)}\ 20\% \qquad \textbf{(D)}\ 21\% \qquad \textbf{(E)}\ 40\%

Full credit goes to MAA for authoring these problems. These problems were taken on the AOPS website.