To build a road, the ratio of the length of the repaired to the unrepaired is 1:4. After repairing 75 meters, the ratio of the length of the repaired to the unrepaired is 8:17. What is the length of the road in meters?
修一条公路，已修的和未修的长度之比是1：4，再修75米后，已修和未修的长度之比是8：17，则这条公路长是多少米．
<gadget id="calculator">8 + 17</gadget>
<output>25</output>

<gadget id="calculator">8 / 25</gadget>
<output>8/25 = around 0.32</output>

<gadget id="calculator">1 + 4</gadget>
<output>5</output>

<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">(8/25) - (1/5)</gadget>
<output>3/25 = around 0.12</output>

<gadget id="calculator">75 / (3/25)</gadget>
<output>625</output>

<result>625</result>