商场销售一批衬衫,平均每天可售出20件,每件盈利40元,为了扩大销售,增加盈利,尽快减少库存,商场决定降价,调查发现,如果每件降价1元,商场每天可多售出2件,若商场每天要盈利1200元,每件应降价多少元
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某工程队在我市拆迁,原计划每天拆迁1250㎡,第一天少拆迁了20%,从第二天开始加快了速度,第三天茶钱了1440㎡
求①该工程队第一天拆迁的面积
②若该队第二天第三天的拆迁面积比前一天增长了百分数相同,求这个百分数