A person rowed a small boat to the upper reaches of the river, and accidentally dropped the kettle into the river just as he started. When he found out and fell over the bow, the kettle was already 4 kilometers away from the boat. Assume that the speed of the boat is 12 kilometers per hour. The speed is 2.4 kilometers per hour, so how many kilometers away from the starting point when he catches up with the kettle?
某人划一条小船驶向河流上游，刚出发就不慎把水壶掉入河中，当他发现并且掉过船头的时候，水壶已经距离船4千米，假定小船速度是每小时12千米，水流速度每小时2.4千米，那么他追上水壶时距离出发点多少千米？
<gadget id="calculator">12 + 2.4</gadget>
<output>14.4</output>

<gadget id="calculator">4 / 14.4</gadget>
<output>0.277778</output>

<gadget id="calculator">12 - 2.4</gadget>
<output>9.6</output>

<gadget id="calculator">4 / 9.6</gadget>
<output>0.416667</output>

<gadget id="calculator">0.277778 + 0.416667</gadget>
<output>0.694445</output>

<gadget id="calculator">2.4 * 0.694445</gadget>
<output>1.666668</output>

<result>1.666668</result>