<PRE><B>Question 205942</B>
Mariko can finish the typing job in 5 hrs. 
If Monique helps her, they can finish the same job in three hrs.
 How long would it take Monique to finish the typing job alone?
:
Let x = amt of time required for Monique to do the job alone
:
Let the completed job = 1
;
Each will do a faction of the job, the two fraction add up to 1:
{{{3/5}}} + {{{3/x}}} = 1
:
Multiply equation by 5x to get rid of the denominator, results:
3x + 3(5) = 5x
:
15 = 5x - 3x
:
15 = 2x
x = {{{15/2}}}
x = 7.5 hrs working alone
:
:
Is this true:
{{{3/5}}} + {{{3/7.5}}} = 
.6 + .4 = 1 </PRE>