# Related rates (multiple rates)

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### Problem

The height of a rectangle is increasing at a rate of 11 centimeters per hour and the width of the rectangle is decreasing at a rate of 9 centimeters per hour.
At a certain instant, the height is 3 centimeters and the width is 8 centimeters.
What is the rate of change of the area of the rectangle at that instant (in square centimeters per hour)?