A barrel of gasoline uses up (3/10) of the total for the first time, uses up the remaining (1/7) of the first time for the second time, uses up (1/3) for the third time, and now There are 50 kilograms left. How many kilograms does this barrel of oil weigh?
一桶汽油第一次用去总数的(3/10)，第二次用去第一次剩下的(1/7)，第三次用去第二次剩下(1/3)，现在还剩下50千克，这桶油原来重多少千克？
<gadget id="calculator">3 / 10</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">1 - (3/10)</gadget>
<output>7/10 = around 0.7</output>

<gadget id="calculator">1 / 7</gadget>
<output>1/7 = around 0.142857</output>

<gadget id="calculator">(7/10) * (1/7)</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">1 - (3/10) - (1/10)</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

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

<gadget id="calculator">1 - (3/10) - (1/10) - (1/5)</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">50 / (2/5)</gadget>
<output>125</output>

<result>125</result>