Question 469705
Fred can paint a house in 10 hours.
 Together, Pat and Fred can paint the house in 8 hours.
 Which equation, when solved, will produce the number of hours needed for Pat to paint the house alone?
;
Let t = time required by Pat to do the job alone
Let the completed job = 1 (a painted house)
:
Each man will do a fraction of the job, the sum of the two fractions = 1
;
{{{8/10}}} + {{{8/t}}} = 1
multiply by 10t, results:
8t + 8(10) = 10t
80 = 10 - 8t
80 = 2t
t = {{{80/2}}}
t = 40 hrs, for Pat to do it alone, (fire this guy)
:
Check this
8/10 + 8/40 = 
.8 + .2 = 1