Question 342164
A plumber and an assistant finished a job in 4h.
 The job would have taken the plumber 6 h working alone.
 how long would the job have taken the assistant working alone?
;
Let a = time required by assistant working alone
;
Let the completed job = 1
:
{{{4/6}}} + {{{4/a}}} = 1
multiply by 6a, results:
4a + 6(4) = 6a
24 = 6a - 4a
24 = 2a
a = {{{24/2}}}
a = 12 hrs, assistant alone