A bucket of water uses 20% of the whole bucket for the first time, 10 kilograms for the second time, and the sum of the previous two times for the third time. At this time, there are still 4 kilograms of water in the bucket. How many kilograms does this bucket of water weigh?
一桶水第一次用去全桶的20%，第二次用去10千克，第三次用了前两次的和，这时桶里还剩下4千克水．问这桶水有多少千克？
<gadget id="calculator">10 + 10 + 4</gadget>
<output>24</output>

<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

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

<gadget id="calculator">24 / (3/5)</gadget>
<output>40</output>

<result>40</result>