Xinxin brand ventilator used to cost 150 yuan per unit, but it was reduced to 120 yuan per unit during the summer promotion. How much is the price cut?
欣欣牌换气扇原来每台售价150元，夏季促销时每台降低到120元，降价了百分之几？
<gadget id="calculator">150 - 120</gadget>
<output>30</output>

<gadget id="calculator">30 / 150</gadget>
<output>1/5 = around 0.2</output>

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