Processing 1620 parts, if A and B start working at the same time, it can be completed in 6 hours. It is known that A processes 150 pieces per hour, how many pieces does B process per hour?
加工1620个零件，如果甲乙两人同时开工，6小时可以完成．已知甲每小时加工150个，乙每小时加工多少个？
<gadget id="calculator">150 * 6</gadget>
<output>900</output>

<gadget id="calculator">1_620 - 900</gadget>
<output>720</output>

<gadget id="calculator">720 / 6</gadget>
<output>120</output>

<result>120</result>