Mingming, Panpan, and Nana set off from the school to the park at the same time. The speeds of Mingming and Panpan were 20 meters per minute and 16 meters per minute respectively. At the same time as they started, Dongdong came from the park. , met Mingming, Panpan, and Nana at 6, 7, and 8 minutes after they set off, and asked for Nana's speed.
明明、盼盼、娜娜三人同时从学校出发到公园去，明明、盼盼两人的速度分别是每分钟20米和每分钟16米，在他们出发的同时，东东从公园迎面走来，分别在他们出发后6分、7分、8分先后与明明、盼盼、娜娜相遇，求娜娜的速度．
<gadget id="calculator">20 * 6</gadget>
<output>120</output>

<gadget id="calculator">20 - 16</gadget>
<output>4</output>

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

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

<gadget id="calculator">4 * 6</gadget>
<output>24</output>

<gadget id="calculator">24 - 16</gadget>
<output>8</output>

<gadget id="calculator">8 * 2</gadget>
<output>16</output>

<gadget id="calculator">120 - 16</gadget>
<output>104</output>

<gadget id="calculator">104 / 8</gadget>
<output>13</output>

<result>13</result>