<PRE><B>Question 424737</B>
larry can paint the walls of his apartment in 8h. after he has worked for 3h,
 patrick joins him , and together they finish the job in 2h.
 how long would it take patrick to do the entire painting job without larry?
: 
let p = time required by Pat doing the job alone
let the completed job = 1
:
From the given information we know: L worked 5 hrs and P worked 2 hrs
:
{{{5/8}}} + {{{2/p}}} = 1
multiply by 8p to clear the denominators, results:
5p + 8(2) = 8p
16 = 8p - 5p
16 = 3p
p = {{{16/3}}}
p = 5{{{1/3}}} hrs alone
:
:
Check this using decimals
5/8 + 2/5.33
.625 + .375 = 1.0</PRE>