A processing workshop needs to process 875 parts. It has been processed for 3.5 hours, processing 50 parts per hour, and the rest are processing 70 parts per hour on average. How many hours will it take to complete the task?
一个加工车间要加工875个零件，已经加工了3.5小时，每小时加工50个，剩下的平均每小时加工70个，还要几小时完成任务？
<gadget id="calculator">50 * 3.5</gadget>
<output>175</output>

<gadget id="calculator">875 - 175</gadget>
<output>700</output>

<gadget id="calculator">700 / 70</gadget>
<output>10</output>

<result>10</result>