# how to discover the duration of liquid fulfillment?

what's a good way to find out how long it would take to fill my rubber ducky with water so it can sink and rescue my ring? for simplicity sake, my ducky sinks when 100% full. an example of a kinda the same problem using a box being filled with water can be seen around the 9 min mark or so -- http://www.youtube.com/watch?v=NWUFjb8w9Ps

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A good way to find out is with a stopwatch. Have you wandered onto this site by mistake? –  Gerry Myerson Nov 19 '12 at 8:16
About 6:50 would be better –  Henry Nov 19 '12 at 8:16

If the volume of your duck is $D$ and the rate at which water is added is a constant $r$ then presumably $\dfrac{D}{r}$. If $r$ varies over time then the solution to $\int_{s=0}^t r \,ds = D$.