To evaporate a certain amount of water from 150 kg of brine with a salt content of 16% to obtain a brine with a saline content of 20%, how many kilograms of water should be evaporated? (solution by equation)
要从含盐16%的150千克盐水中蒸发掉一定的水，得到含盐20%的盐水，应蒸发掉多少千克的水？(用方程解)
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">150 * (1/5)</gadget>
<output>30</output>

<gadget id="calculator">16 / 100</gadget>
<output>4/25 = around 0.16</output>

<gadget id="calculator">150 * (4/25)</gadget>
<output>24</output>

<gadget id="calculator">30 - 24</gadget>
<output>6</output>

<gadget id="calculator">6 / (1/5)</gadget>
<output>30</output>

<result>30</result>