Question 829894
These are their rates in jobs per hour:
Woman, 1/5
Daughter, 1/7
Husband, 1/x


Uniform rates problems are as {{{R*t=j}}}:   Rate, time, job.


1 hour woman & daughter together.
4 hours woman & daughter & husband.


{{{highlight((1/5+1/7)*1+(1/5+1/7+1/x)*4=1)}}} ----- that is the equation in raw form for the one job to become done.  Solve for x.



To begin solving that equation, multiply left and right members by the simplest common denominator, {{{37x}}}.  This will clear the fractions.  You do the rest.