SOLUTION: It takes Brenda 15 hours to clean an attic. Danielle can clean the same attic in 13 hours. How long would it take them if they worked together.

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Question 1041930: It takes Brenda 15 hours to clean an attic. Danielle can clean the same attic in 13 hours. How long would it take them if they worked together.
Found 2 solutions by josmiceli, Edwin McCravy:
Answer by josmiceli(19441)   (Show Source): You can put this solution on YOUR website!
Brenda's rate of working:
[ 1 attic cleaned ] / [ 15 hrs ]
Danielle's rate of working:
[ 1 attic cleaned ] / [ 13 hrs ]
-------------------------
Add their rates of working to get
their rate working together
Let = time in hrs for them to
clean the attic working together

Multiply both sides by



hrs
--------------------
check the answer:



OK

Answer by Edwin McCravy(20056)   (Show Source): You can put this solution on YOUR website!

Their rates are  and 

Their combined rate is the sum of their rates . 

Since 

Then since they are to do 1 job, the number of jobs is 1, and



Multiply top and bottom by LCD = 15∙13=195











Edwin

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