Dr. Zhang needs 75% alcohol to see a patient. Now there is 18kg of 95% alcohol. How many kilograms of water do we need to add?
张大夫给病人看病，需要75%的酒精，现在有95%的酒精18kg，需要加水多少千克？
<gadget id="calculator">95 / 100</gadget>
<output>19/20 = around 0.95</output>

<gadget id="calculator">75 / 100</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">(19/20) / (3/4)</gadget>
<output>19/15 = around 1.266667</output>

<gadget id="calculator">18 * (19/15)</gadget>
<output>114/5 = around 22.8</output>

<gadget id="calculator">(114/5) - 18</gadget>
<output>24/5 = around 4.8</output>

<result>24/5 = around 4.8</result>