In 2007, the national railway was speeded up for the sixth time. A train traveled 200 kilometers per hour from Shanghai to Beijing, and it took 7.5 hours to get there, 4.5 hours faster than before. How many kilometers per hour did the train travel.
2007年全国铁路第六次大提速，一列火车从上海开往北京每小时行驶200千米，7.5小时可以到达，比原来快了4.5小时，这列火车原来每小时行驶多少千米．
<gadget id="calculator">7.5 + 4.5</gadget>
<output>12</output>

<gadget id="calculator">7.5 / 12</gadget>
<output>0.625</output>

<gadget id="calculator">200 * 0.625</gadget>
<output>125</output>

<result>125</result>