The garment factory wants to produce a batch of children's clothing. The original plan is to produce 350 sets per day, which will be completed in 48 days. 420 sets are actually produced every day, how many days are actually used? (Use X to represent the unknown, column formula solution)
服装厂要生产一批儿童服装，原计划每天生产350套，48天完成．实际每天生产420套，实际用多少天？(用X表示未知数，列式解答)
<gadget id="calculator">350 * 48</gadget>
<output>16_800</output>

<gadget id="calculator">16_800 / 420</gadget>
<output>40</output>

<result>40</result>