Hefei Baida Electric bought a batch of air conditioners, sold 1/5 of the total in the first week, and sold 40 more than 1/4 of the total in the second week, leaving 400 units. How many batches of air conditioners are there?
合肥百大电器购进一批空调，第一周售出了总数的(1/5)，第二周售出的比总数的(1/4)多40台，这时还剩400台，这批空调共有多少台？
<gadget id="calculator">400 + 40</gadget>
<output>440</output>

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

<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 - (1/5) - (1/4)</gadget>
<output>11/20 = around 0.55</output>

<gadget id="calculator">440 / (11/20)</gadget>
<output>800</output>

<result>800</result>