To prepare a physiological saline, the mass ratio of salt to water is 1:25, if there are 18 kg of salt, how much water should be added?
配制一种生理盐水，盐和水的质量比是1：25，如果有盐18千克，需加水多少千克？
<gadget id="calculator">18 / 1</gadget>
<output>18</output>

<gadget id="calculator">18 * 25</gadget>
<output>450</output>

<result>450</result>