Question 188897
Let {{{1/x}}}=the amount of work that can be done by second member in an hour

If 1/4 of the work can be done by both in an hour, then :

{{{(1/4)-(1/x)=(1/6)}}}

Multiply both sides by 12x, we get:

{{{3x-12=2x}}}

{{{3x-2x=12}}}

{{{x=12}}}

Then working alone, the second worker can finish the job in 12 hours.