There is a sloping road 45 kilometers long. The carriage goes down 10 kilometers per hour, and the charge is 4 yuan. The uphill travels 5 kilometers per hour, and the toll is 5.5 yuan. Today, there are two carriages carrying passengers at both ends of the slope. When the two carriages meet on the way, the two carriages exchange passengers and then return to the original place. Question: How should the drivers of the two carriages settle the fare?
有一坡路长45千米，马车下破每小时行10千米，收费4元，上坡每小时行5千米，收费5.5元，今有两马车在这坡路的两端各载客人出发相向而行，车费在两车出发时各已付清，当两车在途中相遇时，两马车交换乘客后即返回原地，问：两马车的驾车人应怎样结算车费？
<gadget id="calculator">10 + 5</gadget>
<output>15</output>

<gadget id="calculator">45 / 15 / 10</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">10 * (3/10) * 4</gadget>
<output>12</output>

<gadget id="calculator">45 / 15 / 5</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">10 * (3/5) * 5.5</gadget>
<output>33</output>

<gadget id="calculator">45 / 10</gadget>
<output>9/2 = around 4.5</output>

<gadget id="calculator">(9/2) * 4</gadget>
<output>18</output>

<gadget id="calculator">33 - 18</gadget>
<output>15</output>

<gadget id="calculator">12 + 15</gadget>
<output>27</output>

<result>27</result>