The construction bureau is building a road. The length of the road that has been repaired is 100 meters longer than the road that has not been repaired. The ratio of the length of the road that has been repaired to the length of the road that has not been repaired is 5:4.
建设局修一条公路，已修的比没修的多100米，已修的和没修的长度比是5：4，这条公路全长多少米？
<gadget id="calculator">400 + 100</gadget>
<output>500</output>

<gadget id="calculator">500 + 400</gadget>
<output>900</output>

<result>900</result>