A rope is several meters long, the number of meters used for the first time is 10 meters less than the total length of the rope (3/8), and the number of meters used for the second time is 40 meters more than the remaining (2/5) , there are 260 meters left at this time, what is the total length of this rope in meters?
一条绳长若干米，第一次用去的米数比这根绳的全长的(3/8)少10米，第二次用去的米数比余下的(2/5)多40米，这时还剩下260米，这根绳子的全长是多少米？
<gadget id="calculator">260 + 40</gadget>
<output>300</output>

<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 - (2/5)</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">300 / (3/5)</gadget>
<output>500</output>

<gadget id="calculator">500 - 10</gadget>
<output>490</output>

<gadget id="calculator">3 / 8</gadget>
<output>3/8 = around 0.375</output>

<gadget id="calculator">1 - (3/8)</gadget>
<output>5/8 = around 0.625</output>

<gadget id="calculator">490 / (5/8)</gadget>
<output>784</output>

<result>784</result>