Update main.tex

Author: annadavismath

SYS-0030/main.tex

@@ -724,13 +724,13 @@ \section*{Practice Problems}
 
 
 \begin{problem}\label{prob:rankofmat5}
-Suppose $A$ is a matrix with 5 rows and 7 columns.  Which of the following can be true?
-\begin{multipleChoice}
+Suppose $A$ is a matrix with 5 rows and 7 columns.  Which of the following is possible?
+\begin{selectAll}
  \choice{$\mbox{rank}(A)=7$}
  \choice{$\mbox{rank}(A)=6$}
  \choice[correct]{$\mbox{rank}(A)=5$}
- \choice{All of the above}
- \end{multipleChoice}
+ \choice[correct]{$\mbox{rank}(A)=4$}
+ \end{selectAll}
 \end{problem}
 
 \begin{problem}\label{prob:4eq5un}