Three people buy things together, 1/2 of what A pays is exactly what B pays (1/3), and what C pays (2/7), it is known that C pays 120 yuan more than A, then the total How much did you pay?
三人合买东西，甲付钱的1/2恰为乙所付的(1/3)，又恰为丙付钱的(2/7)，已知丙比甲多付120元，那么一共付了多少元？
<gadget id="calculator">7 / 17</gadget>
<output>7/17 = around 0.411765</output>

<gadget id="calculator">4 / 17</gadget>
<output>4/17 = around 0.235294</output>

<gadget id="calculator">(7/17) - (4/17)</gadget>
<output>3/17 = around 0.176471</output>

<gadget id="calculator">120 / (3/17)</gadget>
<output>680</output>

<result>680</result>