Question 896951
Let x = time for Chris to do the job himself alone.


Rates of Work For Each Worker:
John, {{{1/(x+2)}}}
Chris, {{{1/x}}}


RT=J for Rate, Time, Job.


Account for the 1 job which John and Chris do.
{{{highlight_green((1/(x+2))*1+(1/(x+2)+1/x)*3=1)}}}.
This is amount of job John does in 1 hour plus amount of job both John and Crhis do together for 3 hours.
Solve for x and then evaluate x+2.


Begin recognizing the lowest common denominator is x(x+2); and multiply the members by this, and simplify.
Solve ...