barrel of oil is poured out for the first time (2/7), and the second time is 3kg more than the first time, and the total of the two times is 27kg. How many kilograms does this barrel of oil originally have?
一桶油，第一次倒出(2/7)，第二次比第一次多倒出3kg，两次共倒出27kg，这桶油原来有多少千克？
<gadget id="calculator">27 - 3</gadget>
<output>24</output>

<gadget id="calculator">2 / 7</gadget>
<output>2/7 = around 0.285714</output>

<gadget id="calculator">(2/7) * 2</gadget>
<output>4/7 = around 0.571429</output>

<gadget id="calculator">24 / (4/7)</gadget>
<output>42</output>

<result>42</result>