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At 3 PM a ship which is sailing due south at [math]12[/math] knots is [math]5[/math] miles west of a west-bound hip which is making [math]16[/math] knots.

• At what rate is the distance between the ships changing at 3 PM?
• At what time does the distance between the ships stop decreasing and start increasing?
• What is the shortest distance between the ships?