The school's red scarf station measures the depth of the river, and inserts a pole into the river. (2/15) of the pole is inserted in the mud, and (1/10) is out of the water. When the water surface rises by 12 cm, the water depth just accounts for (5/6) of the benchmark. What was the original depth of the river?
学校红领巾文站测量河水深度，把一根标杆插入河中，标杆的(2/15)插在泥中，(1/10)露出水面．当水面上升12厘米时，水深正好占标杆的(5/6)．河水原来的深度是多少？
<gadget id="calculator">5 / 6</gadget>
<output>5/6 = around 0.833333</output>

<gadget id="calculator">2 / 15</gadget>
<output>2/15 = around 0.133333</output>

<gadget id="calculator">1 / 10</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">1 - (2/15) - (1/10)</gadget>
<output>23/30 = around 0.766667</output>

<gadget id="calculator">(5/6) - (23/30)</gadget>
<output>1/15 = around 0.066667</output>

<gadget id="calculator">12 / (1/15)</gadget>
<output>180</output>

<gadget id="calculator">180 * (5/6)</gadget>
<output>150</output>

<gadget id="calculator">150 - 12</gadget>
<output>138</output>

<result>138</result>