Two bosses, A and B, respectively buy a fashion at the same price, and the number of sets bought by B is 1/8 less than that of A, while A and B sell at a price of 75% and 80% of the profit respectively. After both of them are sold out, A gets a part of the profit more than B, and this part of the profit is just enough for him to buy another 4 sets of this fashion. How many sets of this fashion did A originally buy?
甲、乙两个老板分别以同样的价格购进一种时装，乙购进的套数比甲少(1/8)，而甲、乙分别按获得75%和80%的利润定价出售．两人都全部售完后，甲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4套，甲原来购进这种时装多少套？
<gadget id="calculator">75 / 100</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">(3/4) * 8</gadget>
<output>6</output>

<gadget id="calculator">80 / 100</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">(4/5) * 7</gadget>
<output>28/5 = around 5.6</output>

<gadget id="calculator">6 - (28/5)</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">10 / (2/5)</gadget>
<output>25</output>

<gadget id="calculator">25 * 8</gadget>
<output>200</output>

<result>200</result>