Teacher Zhang from the School General Affairs Office went to the woodware factory to order 240 sets of desks and chairs, each set priced at 80 yuan. Teacher Zhang said to the factory manager: "If the price of one set of desks and chairs is reduced by 1 yuan, I will order 10 more sets." After thinking about it for a long time, the profit obtained by reducing the price of each set of tables and chairs by 10% is the same as the profit obtained by not reducing the price, so I agreed to Mr. Zhang’s request that each set of tables and chairs be reduced by 10%. How much is the cost.
学校总务处张老师到木器厂订做240套课桌椅，每套定价80元，张老师对厂长说："如果1套桌椅每减价1元，我就多定10套．"厂长想了想，每套桌椅减价10%所获得的利润与不减价所获得的利润同样多，于是答应了张老师的要求每套桌椅减价10%，那么每套桌椅的成本是多少元．
<gadget id="calculator">10 / 100</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">80 * (1/10) * 10 * 240</gadget>
<output>19_200</output>

<gadget id="calculator">80 * (1/10) * 10 * 80 * (1/10) * 10</gadget>
<output>6_400</output>

<gadget id="calculator">80 * (1/10) * 240</gadget>
<output>1_920</output>

<gadget id="calculator">80 * (1/10) * 80 * (1/10) * 10</gadget>
<output>640</output>

<gadget id="calculator">240 * 80 * (1/10) * 10</gadget>
<output>19_200</output>

<gadget id="calculator">6_400 - 1_920 - 640 - 19_200</gadget>
<output>-15_360</output>

<gadget id="calculator">19_200 + (-15_360)</gadget>
<output>3_840</output>

<gadget id="calculator">80 * (1/10) * 10</gadget>
<output>80</output>

<gadget id="calculator">80 - 240</gadget>
<output>-160</output>

<gadget id="calculator">240 + (-160)</gadget>
<output>80</output>

<gadget id="calculator">3_840 / 80</gadget>
<output>48</output>

<result>48</result>