A glass bottle contains 500 grams of salt water with a salt content of 15%. How many grams of water should be added to make brine with 5% salinity?
一个玻璃瓶装有含盐率为15%的盐水500克．如要配制成含盐率为5%的盐水，要加入多少克水？
<gadget id="calculator">15 / 100</gadget>
<output>3/20 = around 0.15</output>

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

<gadget id="calculator">(3/20) / (1/20)</gadget>
<output>3</output>

<gadget id="calculator">500 * 3</gadget>
<output>1_500</output>

<gadget id="calculator">1_500 - 500</gadget>
<output>1_000</output>

<result>1_000</result>