To build a road, build 45 meters per day, and finish it in exactly 20 days, which is 4 days less than the original plan. How many meters was originally planned to be repaired per day? (Solve with ratio)
修一条路，每天修45米，正好20天修完，比原计划节约了4天，原计划每天修多少米？(用比例解)
<gadget id="calculator">45 * 20</gadget>
<output>900</output>

<gadget id="calculator">20 + 4</gadget>
<output>24</output>

<gadget id="calculator">900 / 24</gadget>
<output>75/2 = around 37.5</output>

<result>75/2 = around 37.5</result>