There are 15 liters of oil in two barrels. After 3 liters of oil are used up in the small barrel, the mass ratio of the remaining oil to the oil in the big barrel is 1:5. How many liters of oil are there in the big barrel?
两桶油共15升，小桶的油用去3升后，剩下的油与大桶中的油的质量比是1：5，大桶中有多少升油？
<gadget id="calculator">15 - 3</gadget>
<output>12</output>

<gadget id="calculator">1 + 5</gadget>
<output>6</output>

<gadget id="calculator">5 / 6</gadget>
<output>5/6 = around 0.833333</output>

<gadget id="calculator">12 * (5/6)</gadget>
<output>10</output>

<result>10</result>