For a bucket of boiling water, use a thermos bottle of the same size to make it. After filling 3 bottles, there will be (6/7) left in the barrel, and after filling 7 more bottles, there will be 22 kg left in the barrel. How many kilograms of boiling water can this bucket hold?
一桶开水，用同样大小的热水瓶去打．注满3瓶后，桶内还剩下(6/7)，再注满7瓶后，桶内还剩下22千克．这个桶能装开水多少千克？
<gadget id="calculator">6 / 7</gadget>
<output>6/7 = around 0.857143</output>

<gadget id="calculator">1 - (6/7)</gadget>
<output>1/7 = around 0.142857</output>

<gadget id="calculator">3 / (1/7)</gadget>
<output>21</output>

<gadget id="calculator">21 - 7 - 3</gadget>
<output>11</output>

<gadget id="calculator">22 / 11</gadget>
<output>2</output>

<gadget id="calculator">2 * 21</gadget>
<output>42</output>

<result>42</result>