Several liters of 70% salt solution are mixed with some 58% salt solution to obtain a 62% salt solution. If each solution takes 15 liters more and mixed to obtain a 63.25% salt solution, then the first How many liters of a solution containing 70% salt were taken during the first mixing.
若干升含盐70%的溶液与若干含盐58%的溶液混合后得到含盐62%的溶液，如果每种溶液各多取15升，混合后就得到含盐63.25%的溶液，那么第一次混合时含盐70%的溶液取了多少升．
<gadget id="calculator">15 * 70</gadget>
<output>1_050</output>

<gadget id="calculator">58 * 15</gadget>
<output>870</output>

<gadget id="calculator">15 * 63.25</gadget>
<output>948.75</output>

<gadget id="calculator">63.25 * 15</gadget>
<output>948.75</output>

<gadget id="calculator">870 - 948.75 - 948.75</gadget>
<output>-1_027.5</output>

<gadget id="calculator">1_050 + (-1_027.5)</gadget>
<output>22.5</output>

<gadget id="calculator">63.25 * 2</gadget>
<output>126.5</output>

<gadget id="calculator">58 * 2</gadget>
<output>116</output>

<gadget id="calculator">126.5 - 70 - 116</gadget>
<output>-59.5</output>

<gadget id="calculator">63.25 + (-59.5)</gadget>
<output>3.75</output>

<gadget id="calculator">22.5 / 3.75</gadget>
<output>6</output>

<result>6</result>