Three wooden sticks ABC are inserted into the pool, (3/4) of A stick is exposed to the water surface, (4/7) of B stick is exposed to the water surface, and (2/3) of C stick is exposed to the water surface. The total length of the three wooden sticks is 840 cm. How many centimeters deep?
有ABC三根木棒插入水池中，A棒有(3/4)露出水面，B棒有(4/7)露出水面，C棒有(2/3)露出水面，三根木棒总长840厘米，水池深多少厘米？
<gadget id="calculator">12 + 7 + 5</gadget>
<output>24</output>

<gadget id="calculator">12 / 24</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">840 * (1/2)</gadget>
<output>420</output>

<gadget id="calculator">3 / 4</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">1 - (3/4)</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">420 * (1/4)</gadget>
<output>105</output>

<result>105</result>