Last year, the production of 500,000 units was 100,000 units more than the original plan. What percentage was the increase? what is the correct formula
去年生产50万台比原计划多生产10万台，增产了百分之几？正确算式是多少
<gadget id="calculator">50 - 10</gadget>
<output>40</output>

<gadget id="calculator">10 / 40</gadget>
<output>1/4 = around 0.25</output>

<result>1/4 = around 0.25</result>