The fast train and the slow train respectively depart from two stations A and B at the same time. After 1.8 hours, the two trains meet at a distance of 18 kilometers from the midpoint. It is known that the average speed of the slow train is 90 kilometers per hour. What is the average speed of the express train in kilometers per hour?
快、慢两车分别从甲、乙两站同时相对开出，经过1.8小时两车相遇在离中点18千米处，已知慢车平均时速为90千米，快车平均时速是多少千米？
<gadget id="calculator">90 * 1.8</gadget>
<output>162</output>

<gadget id="calculator">18 * 2</gadget>
<output>36</output>

<gadget id="calculator">162 + 36</gadget>
<output>198</output>

<gadget id="calculator">198 / 1.8</gadget>
<output>110</output>

<result>110</result>