The ratio of medicine powder to water in a medicine is 1:200, and the existing medicine powder is 75 grams, how many kilograms of water should be added.
一种药水的药粉和水的比是1：200，现有药粉75克，应加水多少千克．
<gadget id="calculator">200 / 1</gadget>
<output>200</output>

<gadget id="calculator">200 / 1_000</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">75 * (1/5)</gadget>
<output>15</output>

<result>15</result>