For a piece of iron wire, 40% of the total length is used for the first time, and 35 meters for the second time. The ratio of the remaining to the used is 1:3. How many meters is left on this wire?
一根铁丝，第一次用去全长的40%，第二次用去35米，剩下的与用去的比是1：3．这根铁丝还剩多少米？
<gadget id="calculator">40 / 100</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 + 3</gadget>
<output>4</output>

<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 - (2/5) - (1/4)</gadget>
<output>7/20 = around 0.35</output>

<gadget id="calculator">35 / (7/20)</gadget>
<output>100</output>

<gadget id="calculator">100 * (1/4)</gadget>
<output>25</output>

<result>25</result>