A knife costs 3 yuan. If Xiao Ming buys this knife, then the money ratio between Xiao Ming and Xiao Qiang is 2:5; if Xiao Qiang buys this knife, then the money ratio between the two is 8:13. How much money did Xiao Ming have?
一把小刀售价3元．如果小明买了这把小刀，那么小明与小强的钱数之比是2：5；如果小强买了这把小刀，那么两人的钱数之比是8：13．小明原来有多少元钱？
<gadget id="calculator">8 + 13</gadget>
<output>21</output>

<gadget id="calculator">2 + 5</gadget>
<output>7</output>

<gadget id="calculator">21 / 7</gadget>
<output>3</output>

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

<gadget id="calculator">8 - 6</gadget>
<output>2</output>

<gadget id="calculator">3 / 2</gadget>
<output>3/2 = around 1.5</output>

<gadget id="calculator">(3/2) * 8</gadget>
<output>12</output>

<result>12</result>