Boss Zhang said: "I bought a batch of shoes at a price of 6.6 yuan per pair, and sold them at a price of 8 yuan per pair. Today only (1/10) is left. All the money has been recovered and a profit has been made. 240 yuan", how many pairs of this kind of shoes did he buy?
张老板说："我以每双6.6元的价钱购进一批鞋．又以每双8元的价格卖出．到今天只剩下(1/10)．已收回全部货款，而且已获利240元"，问他购进的这种鞋一共多少双？
<gadget id="calculator">1 / 10</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">(1/10) * 8</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">8 - (4/5) - 6.6</gadget>
<output>0.6</output>

<gadget id="calculator">240 / 0.6</gadget>
<output>400</output>

<result>400</result>