This year, the Beijing-Shanghai high-speed railway was put into operation. A train travels directly from Beijing to Shanghai at a speed of 450 kilometers per hour, and it takes 2/3 of the whole journey in 3 hours. According to this calculation, how many hours does it take for this train to arrive in Shanghai when it departs from Beijing?
今年，北京到上海的高速铁路正是投入运营．一列火车以时速450公里从北京直达上海，3小时就行驶了全程的(2/3)，按这样计算，这列火车从北京开出，几小时可以到达上海？
<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">3 / (2/3) / 450</gadget>
<output>1/100 = around 0.01</output>

<gadget id="calculator">450 * (1/100)</gadget>
<output>9/2 = around 4.5</output>

<result>9/2 = around 4.5</result>