If 150 grams of salt water with a concentration of 8% is present, how many grams of water can be added to obtain salt water with a concentration of 5%.
现有浓度为8%的盐水150克，加入多少克水后能得到浓度为5%的盐水．
<gadget id="calculator">8 / 100</gadget>
<output>2/25 = around 0.08</output>

<gadget id="calculator">5 / 100</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">(2/25) / (1/20)</gadget>
<output>8/5 = around 1.6</output>

<gadget id="calculator">150 * (8/5)</gadget>
<output>240</output>

<gadget id="calculator">240 - 150</gadget>
<output>90</output>

<result>90</result>