There are two trains departing from A and B oppositely at the same time. The slow train travels 70 kilometers per hour, and the express train travels 10 kilometers longer than the slow train per hour. After 4 hours, the two trains travel the entire distance (2/3). On a railway map with a scale of 1:10000000, what is the distance in centimeters between A and B on the map?
有两列火车同时从甲、乙两地相对开出，慢车每小时行70千米，快车每小时比慢车多行10千米，4小时后两车行全程的(2/3)．在比例尺是1：10000000的铁路运行图上，甲、乙两地之间的图上距离是多少厘米？
<gadget id="calculator">70 + 70 + 10</gadget>
<output>150</output>

<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">4 / (2/3)</gadget>
<output>6</output>

<gadget id="calculator">1 / 10_000_000</gadget>
<output>1/10_000_000 = around 0</output>

<gadget id="calculator">150 * 6 * 100_000 * (1/10_000_000)</gadget>
<output>9</output>

<result>9</result>