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我市“利民快餐店”试销某种套餐,试销一段时间后发现,每份套餐的成本为5元,该店每天固定支出费用为600元(不含套餐成本).若每份售价不超过10元,每天可销售400份;若每份售价超过10元,每提高1元,每天的销售量就减少40份.为了便于结算,每份套餐的售价x(元)取整数,用y(元)表示该店日纯收入.(日纯收入=每天的销售额﹣套餐成本﹣每天固定支出)
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    Lisa Pina never thought she would need the fire safety training she received during her apprenticeship(学徒期)as a union painter and dry waller(筑墙工). On Friday morning, she was thanking God she had it.

    On Thursday night, while Pina was babysitting her granddaughter, nephew and two nieces in her sister's apartment, she smelled smoke and realized the apartment building was on fire. When her 4-year-old granddaughter Ilean Garcia began saying, “We're going to die, ”she knew she had to act.Pina,39, first sealed the door, and then told all four children to get on the floor. After calling 911, she told the children to start singing and promised them all treats as soon as they reached safety. “I said, ‘OK, we're going to lie down and we're all going to play a game,'” Pina said. “We all started singing our ABCs and 123s.I was just trying to make it fun.” Pina patiently waited, and a few minutes later, Riverside County sheriff's deputies (治安官的助手) arrived. Pina, Ilean,8yearold Gabriel Parga,5-year-old Aubreyana Parga and 4-year-old Meriyah Parga were all trapped on the second floor as flames filled the first story.  Pina did the only thing she could. She opened the window and dropped the children, one-by-one, into the arms of the sheriff's deputies about 15 to 20 feet below. “I just needed to keep the kids calm so they wouldn't be afraid,”Pina said.“I was deathly afraid inside,but I couldn't let them know that.”Not long after dropping the children out of the window, firefighters arrived with a ladder and rescued her. Ten people were treated at the scene for suffering smoke, but nobody was seriously injured.