Two bosses, A and B, respectively buy a fashion at the same price, and B buys more sets than A (1/5), and then A and B sell at a price of 80% and 50% of the profit respectively. After both of them are sold out, A still gets a part of the profit more than B, and this part of the profit is just enough for him to buy another 10 sets of this fashion, how many sets of this fashion did A originally buy.
甲乙两位老板分别以同样的价格购进一种时装，乙购进的套数比甲多(1/5)，然后甲、乙分别按获得80%和50%的利润定价出售．两人都全部售完后，甲仍比乙多获得一部分利润，这部分利润又恰好够他再购进这种时装10套，甲原来购进这种时装多少套．
<gadget id="calculator">80 / 100</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">5 * (4/5)</gadget>
<output>4</output>

<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

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

<gadget id="calculator">5 + 1</gadget>
<output>6</output>

<gadget id="calculator">50 / 100</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">6 * (1/2)</gadget>
<output>3</output>

<gadget id="calculator">4 - 3</gadget>
<output>1</output>

<gadget id="calculator">10 / 1</gadget>
<output>10</output>

<gadget id="calculator">10 * 5</gadget>
<output>50</output>

<result>50</result>