A rope is used up 2.5m, and the used part just accounts for 1/3 of the total length. How long is this rope in meters?
一根绳子用去了2.5m，用去的部分正好占全长的(1/3)．这根绳子全长多少米？
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">2.5 / (1/3)</gadget>
<output>7.5</output>

<result>7.5</result>