题目

水果店张阿姨以每斤2元的价格购进某种水果若干斤，然后以每斤4元的价格出售，每天可售出100斤．通过调查发现，这种水果每斤的售价每降低0.1元，每天可多售出20斤．为保证每天至少售出260斤，张阿姨决定降价销售．销售这种水果要想每天盈利300元，张阿姨需将每斤的售价降低多少元？ 答案：【答案】要想每天盈利300元，张阿姨需将每斤的售价降低1元；【解析】本题为一元二次方程的典型应用，设每斤水果降价x元，则每天多售出200x斤，根据每日利润=每斤利润×销售数量，即可得出关于x的一元二次方程，解之即可得出x的值，再根据每天至少售出260斤，即可得出关于x的一元一次不等式，解 1.The children’s mother was very c________ about their safety when they didn’t come back from school at the usual time. 2. I s________ from a bad cold the other day. It took me days to get rid of it. 3. He will g__________ from the Peking University in four years. 4.The boss was _______（完全地）satisfied with what the workers had done. 5.The teacher i_______ that we should hand in the homework at once. 6.He music is very popular with ________(青少年). 7.You must tell me which kind of _________(交通；运输) you prefer to use. 8.It is said that a group of ________(德国人) will pay a visit to our school this week. 9. I want to have a talk with her, but she i________ me and went away. 10.The boy fell in love with the pretty girl g_________(逐渐的).