There are 150 workers in an auto parts factory, each of whom can produce 200 parts per day on average. Later, the equipment of some workers was improved, and each of these workers could produce 30 more parts per day. At this time, the factory could produce 213 parts per person per day on average. May I ask: How many workers have their equipment improved?
汽车配件厂有150名工人，平均每人每天能生产200个零件．后来部分工人的设备被改良了，这些工人每人每天可以多生产30个零件，此时工厂平均每人每天能生产213个零件．请问：有多少名工人的设备被改良了？
<gadget id="calculator">150 * 213</gadget>
<output>31_950</output>

<gadget id="calculator">150 * 200</gadget>
<output>30_000</output>

<gadget id="calculator">31_950 - 30_000</gadget>
<output>1_950</output>

<gadget id="calculator">30 - 200</gadget>
<output>-170</output>

<gadget id="calculator">200 + (-170)</gadget>
<output>30</output>

<gadget id="calculator">1_950 / 30</gadget>
<output>65</output>

<result>65</result>