Pharaoh bought a washing machine for 1600 yuan, 400 yuan cheaper than before the promotion. How many percent cheaper?
老王花1600元买了一台洗衣机，比促销前便宜了400元．便宜百分之几？
<gadget id="calculator">400 / 2_000</gadget>
<output>1/5 = around 0.2</output>

<result>1/5 = around 0.2</result>