SOLUTION: It takes 5 minutes to fill a sink. When full, the sink drains in 10 minutes. How long will it take to fill the sink if you forget to put in the stopper?

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Question 795464: It takes 5 minutes to fill a sink. When full, the sink drains in 10 minutes. How long will it take to fill the sink if you forget to put in the stopper?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Add the positive rate of filling to the
negative rate of draining to get the
rate when you are both filling and
draining
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Rate of filling:
( 1 sink full ) / ( 5 min )
Rate of draining:
( 1 sink drained ) / ( 10 min )
-------------------------
Let +t+ = time to fill sink while
both filling and draining
---------------------
+1%2F5+-+1%2F10+=+1%2Ft+
( note that if the right side is positive,
the result is filling, not draining )
----------------------
Multiply both sides by +10t+
+2t+-+t+=+10+
+t+=+10+
It will it take 10 min to fill the sink if
you forget to put in the stopper