To lay a water pipe, the full length (2/5) has already been laid and there are 15 meters more. At this time, the ratio of the laid length to the remaining length is 3:4. How long is this water pipe in meters?
要铺设一条自来水管道，已铺设了全长的(2/5)还多15米，这时已铺设的长度和剩下的长度比是3：4，这条自来水管道长多少米？
<gadget id="calculator">3 + 4</gadget>
<output>7</output>

<gadget id="calculator">3 / 7</gadget>
<output>3/7 = around 0.428571</output>

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

<gadget id="calculator">(3/7) - (2/5)</gadget>
<output>1/35 = around 0.028571</output>

<gadget id="calculator">15 / (1/35)</gadget>
<output>525</output>

<result>525</result>