A piece of alloy weighs 600 kg, which contains 60% aluminum, 20% tin, and the rest is lead. How many kilograms of lead does this alloy contain?
一块合金重600千克，其中含铝60%，含锡20%，其余是铅．这块合金含铅多少千克？
<gadget id="calculator">60 / 100</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (3/5) - (1/5)</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">600 * (1/5)</gadget>
<output>120</output>

<result>120</result>