<PRE><B>Question 303077</B>
Quinn can refinish hardwood floors four times as fast as Jack.
 They have to refinish 100 ft^2 of flooring. 
Working together, Quinn and Jack can finish the job in 3 hours.
 How long would it take each of them working alone?
:
Let t = time required by Q to complete job alone
then
4t = time required by J
:
Let the completed job (refinishing 100sq/ft) = 1
:
{{{3/t}}} + {{{3/(4t)}}} = 1
multiply each term by 4t, results
4(3) + 3 = 4t
12 + 3 = 4t
15 = 4t
t = {{{15/4}}}
t = 3.75 hrs, Q alone
then
4(3.75) = 15 hrs, J alone
:
:
Check this:
3/3.75 + 3/15 =
.8 + .2 = 1</PRE>