To Hold a Spring That Has Been Stretched from Its $20.0 \mathrm{~cm}$

To hold a spring that has been stretched from its natural length of $20.0 \mathrm{~cm}$ to a length of $30.0 \mathrm{~cm}$ , a force of $20.0 \mathrm{~N}$ is required. Determine the work done when stretching the spring from $30.0 \mathrm{~cm}$ to $37.0 \mathrm{~cm}$ .