A certain brand of mobile phone has a promotional activity, and the price is reduced by 10%. On this basis, the store returns 5% of the selling price in cash. Buying this brand of mobile phone at this time is equivalent to a price reduction of what percentage?
某品牌的手机进行促销活动，降价10%，在此基础上商店又返还售价5%的现金，此时买这个品牌手机，相当于降价百分之几？
<gadget id="calculator">10 / 100</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">1 - (1/10)</gadget>
<output>9/10 = around 0.9</output>

<gadget id="calculator">5 / 100</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">1 - (1/20)</gadget>
<output>19/20 = around 0.95</output>

<gadget id="calculator">(9/10) * (19/20)</gadget>
<output>171/200 = around 0.855</output>

<gadget id="calculator">1 - (171/200)</gadget>
<output>29/200 = around 0.145</output>

<result>29/200 = around 0.145</result>