There is a barrel, which is half full of wine, and (2/5) of the wine is poured out, and there is still 15 kilograms left. How many kilograms of wine can this barrel hold?
有一只桶，装了半桶酒，倒出酒的(2/5)，还剩15千克，这只桶能装多少千克酒？
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 - (2/5)</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">15 / (3/5)</gadget>
<output>25</output>

<gadget id="calculator">25 * 2</gadget>
<output>50</output>

<result>50</result>