batch of TVs is planned to assemble 120 sets per day, which will be completed in 15 days. In fact, 450 units were assembled in the first 3 days. According to this calculation, how many days will it take to complete the assembly? (Solve with ratio)
一批电视，计划每天装配120台，15天完成．实际前3天装配了450台，照这样计算，需要多少天可以装配完？(用比例解)
<gadget id="calculator">120 * 15</gadget>
<output>1_800</output>

<gadget id="calculator">450 / 3</gadget>
<output>150</output>

<gadget id="calculator">1_800 / 150</gadget>
<output>12</output>

<result>12</result>