Two ants, A and B, crawl from both ends of a rope to the middle at the same time. After 20 minutes, the distance is 6 meters. At this time, A has climbed 40% of the total length, and B has climbed 75% of the total length. Ask the rope How many meters long?
甲、乙两只蚂蚁，同时从一根绳子的两端向中间爬，20分钟后相距6米，这时甲爬了全长的40%，乙爬了全长的75%，问这根绳子长多少米？
<gadget id="calculator">40 / 100</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">75 / 100</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">(3/4) - 1</gadget>
<output>-1/4 = around -0.25</output>

<gadget id="calculator">(2/5) + (-1/4)</gadget>
<output>3/20 = around 0.15</output>

<gadget id="calculator">6 / (3/20)</gadget>
<output>40</output>

<result>40</result>