To dig a canal, 15% of the total length has been dug and more than 20 meters have been dug, and there are still 150 meters left to be dug. How long is this canal in meters?
挖一条水渠，已经挖了全长的15%多20米，还剩下150米没有挖．这条水渠全长多少米？
<gadget id="calculator">20 + 150</gadget>
<output>170</output>

<gadget id="calculator">15 / 100</gadget>
<output>3/20 = around 0.15</output>

<gadget id="calculator">1 - (3/20)</gadget>
<output>17/20 = around 0.85</output>

<gadget id="calculator">170 / (17/20)</gadget>
<output>200</output>

<result>200</result>