The Shanghai TV Factory plans to produce 4,200 sets of "Golden Star" color TVs. 2,400 sets have already been produced, and the rest will be completed within 15 days. How many sets are produced on average per day?
上海电视机厂计划生产"金星牌"彩电4200台，已经生产了2400台，剩下的要在15天里完成，平均每天生产多少台？
<gadget id="calculator">4_200 - 2_400</gadget>
<output>1_800</output>

<gadget id="calculator">1_800 / 15</gadget>
<output>120</output>

<result>120</result>