SOLUTION: An empty bathtub can be filled in 15 minutes. When full, the bathtub can be drained in 25 minutes.how long will it take to fill the empty bathtub if the drain is left open ?

Algebra ->  Probability-and-statistics -> SOLUTION: An empty bathtub can be filled in 15 minutes. When full, the bathtub can be drained in 25 minutes.how long will it take to fill the empty bathtub if the drain is left open ?       Log On


   

Question 1134953: An empty bathtub can be filled in 15 minutes. When full, the bathtub can be drained in 25 minutes.how long will it take to fill the empty bathtub if the drain is left open ?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Rate of filling for tub:
[ 1 tub filled ] / [ 15 min ]
Rate of emptying for tub:
[ 1 tub emptied ] / [ 25 min ]
( emptying means a negative sign )
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Let +t+ = time to fill empty tub if
the drain is left open
The rate is:
[ 1 tub filled ] / [ t min ]
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+1%2F15+-+1%2F25+=+1%2Ft+
Multiply both sides by +75t+
+5t+-+3t+=+75+
+2t+=+75+
+t+=+37.5+
It will take 37.5 min