Mathematics

Problem

For a rectangle, the width is always half of its length. If the perimeter is increasing at

9\,\text{cm/s}

, what is the rate at which the width is changing when the perimeter is

30\,\text{cm}

? a)

3\,\text{cm/s}

1.5\,\text{cm/s}

0.75\,\text{cm/s}

4.5\,\text{cm/s}