The highest ticket price for the opening ceremony of the 2012 London Olympic Games is RMB 20,000, and the highest ticket price for the opening ceremony of the 2008 Beijing Olympic Games is RMB 5,000. How much cheaper is the ticket price for the opening ceremony of the Beijing Olympic Games than in London?
2012年伦敦奥运会开幕式门票最高为2万元人民币，2008年北京奥运会开幕式门票最高为5000元人民币，北京奥运会开幕式门票比伦敦便宜了百分之几？
<gadget id="calculator">2 * 10_000</gadget>
<output>20_000</output>

<gadget id="calculator">20_000 - 5_000</gadget>
<output>15_000</output>

<gadget id="calculator">15_000 / 20_000</gadget>
<output>3/4 = around 0.75</output>

<result>3/4 = around 0.75</result>