The store buys a batch of pens at a price of 10 yuan each, and then sells them at a fixed price after adding 40% of the profit. When (3/4) of this batch of pens is sold, it has already made a profit of 240 yuan. How many pens are there in total?
商店以每枝10元的价格购进一批钢笔，加上40%的利润以后定价出售，当卖出这批钢笔的(3/4)时就已经获利240元．这批钢笔共有多少枝．
<gadget id="calculator">3 / 4</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">(3/4) * 14</gadget>
<output>21/2 = around 10.5</output>

<gadget id="calculator">(21/2) - 10</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">240 / (1/2)</gadget>
<output>480</output>

<result>480</result>