On a map with a scale of 1:2,000,000, the distance between A and B is 18.4 cm. The bus and the truck depart from A and B at the same time and meet each other in 4 hours. Given that the speed of the passenger car is 40 kilometers per hour, find the speed of the truck.
在比例尺是1：2000000的地图上，量得甲、乙两地的距离为18.4厘米，客车和货车分别从甲、乙两地同时出发，4小时相遇．已知客车速度是每小时40千米，求货车的速度．
<gadget id="calculator">1 / 2_000_000</gadget>
<output>1/2_000_000 = around 0</output>

<gadget id="calculator">18.4 / (1/2_000_000) / 100_000 / 4</gadget>
<output>92</output>

<gadget id="calculator">92 - 40</gadget>
<output>52</output>

<result>52</result>