There is a glass of 300 grams of salt water with a salt content of 8%, how many grams of water should be added to make the salt content of this glass of salt water 5%?
有一杯300克的盐水，含盐率为8%，要使这杯盐水的含盐率为5%，应加入多少克水？
<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">300 * (8/5)</gadget>
<output>480</output>

<gadget id="calculator">480 - 300</gadget>
<output>180</output>

<result>180</result>