There are 20 kilograms of brine with 15% salt content, how many kilograms of salt should be added to make the brine contain 20% salt? (column equation solution)
有含盐15%的盐水20千克，要使盐水含盐20%，需要加盐多少千克？(列方程解答)
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">(1/5) * 20</gadget>
<output>4</output>

<gadget id="calculator">15 / 100</gadget>
<output>3/20 = around 0.15</output>

<gadget id="calculator">100 / 100</gadget>
<output>1</output>

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

<gadget id="calculator">4 - 3</gadget>
<output>1</output>

<gadget id="calculator">1 - (1/5)</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">1 / (4/5)</gadget>
<output>5/4 = around 1.25</output>

<result>5/4 = around 1.25</result>