Question 747992
This one makes more sense than your almost identical posting.  Completed 1/3 of the job and Will gets injured.


Marcus rate, 2/x jobs per hour
Will rate, 1/x jobs per hour.
time working together was 6 hours, and 1/3 of the job was completed.


{{{highlight((2/x+1/x)*6=1/3)}}}
When we find "x" here, we will know how to compute the rate for each of Marcus and Will.


Finding x:
{{{((2+1)/x)*6=1/3}}}
{{{3/x=1/(18)}}}
{{{x/3=18}}}
{{{x=18/3=6}}}


RATES OF THE TWO PAINTERS:
Marcus, {{{2/x=2/6=1/3}}}, THREE hours to do ONE job, alone.
Will, {{{1/6}}}, six hours to do one job, if alone.


If Marcus does the rest of the job himself, how long will this take him?  Remember, 1/3 of the job was done, so Marcus will do 2/3 of the job.
The situation is a uniform rates situation and so we have {{{r*t=j}}}, where r is rate in jobs per hour, t is time in hours, and j is how many jobs.


His rate is (1/3), so {{{highlight((1/3)y=(2/3))}}} where y is the number of hours to do this 2/3 of the job.
{{{y=(3/1)(2/3)}}}
{{{y=(3/3)(2/1)}}}
{{{highlight(y=2)}}},  TWO HOURS MORE THAN when they worked together.