The total length of the Shanghai-Nanjing Expressway is 274 kilometers. A car starts from Nanjing and travels 75 kilometers per hour. It travels 49 kilometers along the Shanghai-Nanjing Expressway to Shanghai. How many hours will it take to reach Shanghai?
沪宁高速公路全长274千米．一辆汽车从南京出发，每小时行75千米，沿沪宁高速公路开往上海，已经行驶了49千米，还需多少小时才能到达上海？
<gadget id="calculator">274 - 49</gadget>
<output>225</output>

<gadget id="calculator">225 / 75</gadget>
<output>3</output>

<result>3</result>