A piece of wood with a length of 3 meters is sawed every (3/7) meters, and each sawing takes 2 minutes. How many minutes will it take to finish sawing this piece of wood?
一根3米长的木料，每(3/7)米锯一段，每锯一次用2分钟，锯完这根木料共用多少分钟．
<gadget id="calculator">3 / 7</gadget>
<output>3/7 = around 0.428571</output>

<gadget id="calculator">3 / (3/7)</gadget>
<output>7</output>

<gadget id="calculator">7 - 1</gadget>
<output>6</output>

<gadget id="calculator">2 * 6</gadget>
<output>12</output>

<result>12</result>