Question 717532
Just solving the problem as directly as you can may be best.


Painter___________rate__________time___________Amount of jobs
Me________________1/4___________4______________1
Apprentice________1/6___________6______________1
Both of us_______1/4+1/6_______(?)_____________1


Our rate, both of us together, is {{{1/4+1/6=(3+2)/12}}} jobs per hour.  That rate is 5/12 jobs per hour.  Since we really want how many hours per 1 job, we want the reciprocal of 5/12, which is {{{highlight(12/5=2&2/5)}}} hours.  This is definitely a few minutes LESS THAN two and a half hours.