A piece of tin-iron alloy contains about 60% iron, and 12 kilograms of tin. How many kilograms does this alloy weigh?
一块锡铁合金里约含铁60%，其中锡有12千克，这块合金约重多少千克？
<gadget id="calculator">60 / 100</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">1 - (3/5)</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">12 / (2/5)</gadget>
<output>30</output>

<result>30</result>