There are two piles of coal, A and B. Pile A originally had (2/5) tons. After taking out (1/4) tons from pile B and putting it into pile A, the piles of coal A and B have the same amount. Ask how many tons of coal there are in Pile B?
甲、乙两堆煤，甲堆原来有(2/5)吨，从乙堆拿出(1/4)吨放入甲堆后，甲、乙两堆煤就同样多．问乙堆原来有煤多少吨？
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">(1/4) * 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">(2/5) + (1/2)</gadget>
<output>9/10 = around 0.9</output>

<result>9/10 = around 0.9</result>