There are two piles of cement in a construction site with a total of 900 bags. If you take out 40 bags from pile A and put them into pile B, then the amount of cement in pile A is 4 times that of pile B. How many bags of cement are there in pile B?
某建筑工地有两堆水泥共900袋．如果从甲堆取出40袋放入乙堆，这时甲堆的水泥是乙堆的4倍，原来乙堆有水泥多少袋？
<gadget id="calculator">4 + 1</gadget>
<output>5</output>

<gadget id="calculator">900 / 5</gadget>
<output>180</output>

<gadget id="calculator">180 - 40</gadget>
<output>140</output>

<result>140</result>