work energy theorem Questions

A block of mass $10\text{kg}$ is moving in $x$ -direction with a constant speed of $10\text{m/sec}$. It is subjected to a retarding force $F=-0.1x\text{joule/meter}$ during its travel from $x=20\text{meter}$ to $x=30\text{meter}$. Its final kinetic energy will be: