A school spent 20,000 yuan to build a playground, saving 5,000 yuan compared to the planned investment. What percentage was the actual savings?
某校修建操场用了2万元，比计划投资节约了0.5万元，实际节约了百分之几？
<gadget id="calculator">2 + 0.5</gadget>
<output>2.5</output>

<gadget id="calculator">0.5 / 2.5</gadget>
<output>0.2</output>

<result>0.2</result>