Question 1038207

Paul can do a certain job in half the time that Jim requires to do it. Jim worked alone for an hour and stopped; then Paul completed the job in 10 hours. What length of time, in hours, would Paul, working alone, take to do the whole job?
<pre>Working alone, Paul takes: {{{highlight_green(matrix(1,2, 10&1/2, hours))}}} to do the job