The railway from Beijing to Guangzhou is 2,300 kilometers long. A train departs from Beijing and travels 960 kilometers in the first 15 hours. It travels an additional 3 kilometers per hour. How many more hours will it take to reach Guangzhou?
从北京到广州的铁路长2300千米，一列火车从北京开出，前15小时行960千米，每小时多行3千米，还要再行几小时才能到达广州？
<gadget id="calculator">2_300 - 960</gadget>
<output>1_340</output>

<gadget id="calculator">960 / 15</gadget>
<output>64</output>

<gadget id="calculator">64 + 3</gadget>
<output>67</output>

<gadget id="calculator">1_340 / 67</gadget>
<output>20</output>

<result>20</result>