A factory uses 4 machine tools to process 720 parts in 4.5 hours. According to this calculation, it needs to process 560 parts in 2 hours. How many lathes are needed for processing?
某工厂用4台机床4.5小时加工零件720个，照这样计算，2小时要加工560各零件，需要多少台车床加工？
<gadget id="calculator">720 / 4.5 / 4</gadget>
<output>40</output>

<gadget id="calculator">560 / 2 / 40</gadget>
<output>7</output>

<result>7</result>