Separating question and answerline in exam

Question

I´m using the exam package and I would like to separate the answerline from the question, so that all answerslines are at the bottom of each page, together.

So far its working using \vfill before \answerline, but not when the question contains more than one part.

See picture for what I´m trying to achieve.

Answer 1

I was unable to accomplish the question using only the exam class commands. But, using tikz this is rather simple.

Code:

\documentclass[addpoints]{exam}
\usepackage{tikz}
\begin{document}
\pointsinrightmargin
\bracketedpoints
\begin{questions}
\question The seventh term, $u_7$, of an arithmetic sequence is 28. The tenth term, $u_{10}$, of the same sequence is 37.
\begin{parts}
\part[2]Find $d$, the common difference of the sequence.
\part[2]Find $u_1$, the first term of the sequence.
\part[2]Find $S_{200}$, the sum of the first 200 terms of the sequence.
\end{parts}
\begin{tikzpicture}
\draw (0,0) -- (17.5,0) -- (17.5,19) -- (0,19) -- (0,0);
\draw(17.5,4) -- (10,4);
\draw(10,4) -- (10,0);
\node[text width=3cm] at (1.7,18.7) {Working:};
\node[text width=3cm] at (11.7,3.8) {Answers:};
\node[text width=7.1cm] at (13.8,3) {(a)\dotfill};
\node[text width=7.1cm] at (13.8,2) {(b)\dotfill};
\node[text width=7.1cm] at (13.8,1) {(c)\dotfill};
\end{tikzpicture}
\end{questions}
\end{document}

Yields: