Question 448983
Add their rates of working to get their rate
working together.
Let {{{t}}} = time it takes the other printer
to do a job
{{{ 1/9 + 1/t = 1/6 }}}
Multiply both sides by {{{18t}}}
{{{ 2t + 18 = 3t }}}
{{{ t = 18 }}}
It takes the other printer 18 days
 to do the work by himself