Question 717891
Ben plans to take a bath but forgets to close the drain. The bath usually takes ten minutes to fill and 12 minutes to empty. How long will it be before the bath is filled if Ben continues to not notice that the drain is open?
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The spigots add 1/10 of the bath per minute
The drain loses 1/12 of the bath per minute
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Together, 1/10 - 1/12 is added per minute
1/10 - 1/12 = (12 - 10)/120 = 2/120
= 1/60 of the bath per minute
--> 60 minutes per bath to fill.
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He should take a shower, anyway.