Uncle Chen rides a bicycle from A to B, traveling 10 kilometers per hour, arriving at 1:00 pm; traveling 15 kilometers per hour, arriving at 11:00 am. If he wants to arrive at 12:00 noon, how many kilometers should he travel per hour?
陈叔叔骑自行车从甲地到乙地，每小时行10千米，下午1时到达；每小时行15千米，上午11时到达．他想在中午12时到达，每小时应行多少千米．
<gadget id="calculator">13 - 11</gadget>
<output>2</output>

<gadget id="calculator">15 - 10</gadget>
<output>5</output>

<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">15 * (2/5)</gadget>
<output>6</output>

<gadget id="calculator">13 - 12</gadget>
<output>1</output>

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

<gadget id="calculator">6 / 7</gadget>
<output>6/7 = around 0.857143</output>

<gadget id="calculator">10 * (6/7)</gadget>
<output>60/7 = around 8.571429</output>

<result>60/7 = around 8.571429</result>