\
Consider
is the Beth
s time working alone,
is the Bills time working alone and
is the Edies time working alone.
The part of the work done in one hour by three painters is
.
The three painters working together and complete the one work in
.
Hence 

Bill and Edie together can complete the work in
.

.
One day, all three worked in
after Edie left, Beth and Bill required eight more hours to finish the work.

.
The system of equations are
\
Multiply the equation
by
and add to the equation
to eliminate
.


.
Substitute
in equation
.



Multiply the equation
by
and add to the equation
to eliminate
.



Substitute
in
.



.
Therefore, Beth work alone in
, Bill in
and Edie in
to complete the work.
\
Beth work alone in
, Bill in
and Edie in
to complete the work.