Answer
Ellen can type $x\div60$ words per minute
Work Step by Step
Let us assume that Ellen's typing speed is uniform for the entire hour during which she was measured. If Ellen can type $x$ words in an hour, then she can type one-sixtieth of that number of words in a minute, for there are $60$ minutes in an hour. Therefore, to find out the number of words Ellen types in a minute, we divide her hourly word count, $x$, by $60$. This gives us $x\div60$
