Question 1150208
Tara plans to take a bath but forgets to close the drain. 

The bath usually takes 10 minutes to fill 
<pre>
So the rate is 1 tub per 10 minutes or 1/10 tub per minute</pre>
and 12 minutes to empty.<pre> 

So the rate is -1 tub per 12 minutes or -1/12 tub per minute.</pre>

How long will it be before the bath is filled<pre> 
Since it fills faster than it empties, it will eventually be filled

Let the time for filling be t.

We use rate∙time = part of tub filled or emptied by both the faucet
and the drain.  Then set that equal to 1 tubfull.

{{{expr(1/10)*t-expr(1/12)*t=1}}}

Multiply both sides by LCD = 60

{{{6t-5t=60}}}
{{{t=60}}}

Answer: 60 minutes or 1 hour.

Edwin</pre>