Gesang traveled from Lhasa to Gonggar Airport, and the whole journey (9/10) was a tunnel. He walked from the airport to Lhasa, and walked to the place (1/3) of the whole journey, which was 15.4 kilometers away from the tunnel. How many kilometers is the distance from Lhasa to the airport?
格桑从拉萨去贡嘎机场，行驶到全程的(9/10)处是隧道．他从机场往拉萨走，行到全程的(1/3)的地方，距离隧道已有15，4千米．拉萨到机场的距离约有多少千米．
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">9 / 10</gadget>
<output>9/10 = around 0.9</output>

<gadget id="calculator">1 - (9/10)</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">(1/3) - (1/10)</gadget>
<output>7/30 = around 0.233333</output>

<gadget id="calculator">15.4 / (7/30)</gadget>
<output>66</output>

<result>66</result>