Question 1189434
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The solution from the other tutor is fine, but it seems like a lot of work....<br>
Using the standard method for solving a problem like this -- by looking at the fractions of the "job" each "worker" does in 1 minutes -- is much easier.<br>
In 1 minute, the faucet fills 1/20 of the tub; in 1 minute the drain empties 1/10 of the tub.<br>
So in 1 minute the fraction of the tub that is emptied is 1/10-1/20 = 1/20.<br>
Therefore it will take 20 minutes for the whole tub to empty.<br>
ANSWER: 20 minutes<br>