<PRE><B>Question 725110</B>
A carpenter can complete a job in 5 hours.
 After working on the job for 2 hours, an assistant helped finish the job.
 Together they completed the job in 1 hour.
 How long might it take the assistant, working alone, to complete a job similar to this one?
:
let a = time required by the assistant working alone
let the completed job = 1
:
The carpenter worked a total 3 hrs, the assistant for 1 hr,
 a shared work equation
;
{{{3/5}}} + {{{1/a}}} = 1
multiply by 5a, results:
3a + 5(1) = 5a
5 = 5a - 3a
5 = 2a
a = 5/2
a = 2.5 hrs
:
:
Check
{{{3/5}}} + {{{1/2.5}}} = 1</PRE>