The oil in barrel A is 54 kg more than that in barrel B. If 7 kg of oil is poured into barrel B from barrel A, the oil in barrel A is 1.5 times the oil in barrel B. How many kilograms of oil does barrel B contain? (solution by equation)
甲桶油比乙桶油多54千克，如果从甲桶倒入乙桶7千克油后，这时甲桶油是乙桶油的1.5倍，乙桶油原来有油多少千克？(用方程解)
<gadget id="calculator">1.5 * 7</gadget>
<output>10.5</output>

<gadget id="calculator">54 - 7 - 10.5</gadget>
<output>36.5</output>

<gadget id="calculator">1.5 - 1</gadget>
<output>0.5</output>

<gadget id="calculator">36.5 / 0.5</gadget>
<output>73</output>

<result>73</result>