The towel factory needs to produce a batch of towels, 420 per day, half of which can be completed in 15 days. If 450 pieces are produced every day, how many days can the task be completed?
毛巾厂要生产一批毛巾，每天生产420条，15天可以完成一半．如果每天生产450条，多少天可以完成任务？
<gadget id="calculator">2 / 450</gadget>
<output>1/225 = around 0.004444</output>

<gadget id="calculator">420 * 15 * (1/225)</gadget>
<output>28</output>

<result>28</result>