The ratio of the number of "trump cards" owned by Mingming and Honghong is 3:2. After Mingming loses 10 cards to Honghong, the ratio of the number of "trump cards" owned by Mingming and Honghong becomes 7:8. "How many total.
明明和红红各自拥有的"王牌"数量之比是3：2，明明输给红红10张后，明明和红红拥有的数量之比变为7：8，那么他们两个拥有的"王牌"总数是多少张．
<gadget id="calculator">3 + 2</gadget>
<output>5</output>

<gadget id="calculator">3 / 5</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">7 + 8</gadget>
<output>15</output>

<gadget id="calculator">7 / 15</gadget>
<output>7/15 = around 0.466667</output>

<gadget id="calculator">(3/5) - (7/15)</gadget>
<output>2/15 = around 0.133333</output>

<gadget id="calculator">10 / (2/15)</gadget>
<output>75</output>

<result>75</result>