On a 1:4000000 map, the distance between A and B is 7.5cm. Three cars A, B, and C drive from city A to city B at the same time. When A arrives at city B, cars B and C have driven 250km and 200km respectively. So, when B arrives at B city, how far is C from B city?
在一幅1：4000000的地图上，A、B两城的距离是7.5cm．甲、乙、丙三辆小车同时从A城开往B城，甲到达B城时，乙、丙两车分别行驶了250km、200km．那么，当乙到达B城时，丙离B城还有多远？
<gadget id="calculator">1 / 4_000_000</gadget>
<output>1/4_000_000 = around 0</output>

<gadget id="calculator">7.5 / (1/4_000_000) / 100_000</gadget>
<output>300</output>

<gadget id="calculator">300 - 250</gadget>
<output>50</output>

<gadget id="calculator">250 / 200</gadget>
<output>5/4 = around 1.25</output>

<gadget id="calculator">1 / (5/4)</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">50 * (4/5)</gadget>
<output>40</output>

<gadget id="calculator">300 - 200 - 40</gadget>
<output>60</output>

<result>60</result>