ticket for a table tennis match is 40 yuan. After the price is reduced, the audience doubles and the income increases (1/5). Ask how much the price of a ticket will be reduced.
乒乓球赛门票40元一张，降价后观众增加一倍，收入增加(1/5)，问一张门票降价多少元．
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">40 * (1/5)</gadget>
<output>8</output>

<gadget id="calculator">40 + 8</gadget>
<output>48</output>

<gadget id="calculator">48 / 2</gadget>
<output>24</output>

<gadget id="calculator">40 - 24</gadget>
<output>16</output>

<result>16</result>