pool is filled with water in the morning, 1/5 of the water is used in the morning, and another 25 liters are used in the afternoon. At this time, the water in the pool is 2 liters more than half of the pool. How much water was put in the pool in the morning?
一个水池早晨放满了水，上午用去这池水的(1/5)，下午又用去25升，这时水池的水比半池水还多2升，这个水池早晨放了多少水？
<gadget id="calculator">25 + 2</gadget>
<output>27</output>

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

<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">(1/2) - (1/5)</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">27 / (3/10)</gadget>
<output>90</output>

<gadget id="calculator">90 * (1/5)</gadget>
<output>18</output>

<result>18</result>