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12. 解：(1)設總廠原來每周制作帳篷千頂，分廠原來每周制作帳篷千頂．

由題意，得······················································································· 3分

解得所以(千頂)，(千頂)．

答：在趕制帳篷的一周內，總廠、分廠各生產帳篷8千頂、6千頂．····························· 6分

(2)設從(甲市)總廠調配千頂帳篷到災區的地，則總廠調配到災區地的帳篷為千頂，(乙市)分廠調配到災區兩地的帳篷分別為千頂．

甲、乙兩市所需運送帳篷的車輛總數為輛．······························································· 8分

由題意，得．

即．······················································································ 10分

因為，所以隨的增大而減小．

所以，當時，有最小值60．

答：從總廠運送到災區地帳篷8千頂，從分廠運送到災區兩地帳篷分別為1千頂、5千頂時所用車輛最少，最少的車輛為60輛．　　　 12分

11. 解：設生產奧運會標志x套，生產奧運會吉祥物y套．根據題意，得

　 …………………………………………2分

①×2－②得：5x=10000．　

∴ x=2000． ………………………………………………………………6分

把x=2000代入①得：5y=12000．

　　　　 ∴ y=2400． 　

　　 答：該廠能生產奧運會標志2000套，生產奧運會吉祥物2400套．……8分

10. (1)甲隊行進了2小時，乙隊行進了2.5小時．

設乙隊的速度為x，則甲隊為1.5x + 5．

由題意得方程　 2.5x +(1.5x + 5)×2 + 1 = 176．

整理得 5.5x = 165， 解得 x = 30．

∴　 1.5x + 5 = 1.5×30 + 5 = 50．

即甲隊趕路的速度為50 km∕h，乙隊趕路的速度為30 km∕h．

(2)設若由乙隊單獨施工，需x小時才能完成．

則由題意有 　6×()+ 5.5×= 1．

解得　 x = 11．

即乙隊單獨做，需要11小時才能完成任務．

9. 解：(1)設小明他們一共了個成人，個學生，

································································································· 4分

····················································································································· 6分

答：小明他們一共去了7個成人，4個學生．································································ 7分

(2)若按14人購買團體票，則共需(元)

(元)．

購買團體票可省24元．····························································································· 3分

8. 解　 ∵

由②得，③　 ······························································································· 2分

將③代入①，得．解得．代入③，得．

∴原方程組的解為 　　　 6分

7. 解：設生產奧運會標志x套，生產奧運會吉祥物y套，得

解得，答略.

6. .解：設原計劃每天挖土石方x萬立方米，增調人員和設備后每天挖y萬立方米················ 1分

　　　 可列出方程組：···································································· 5分

　　　 解之得：

　 答：原計劃每天挖土石方1.3萬立方米，增調人員和設備后每天挖3.6萬立方米······ 8分

5.

解：設A種帳篷x頂，B種帳篷y頂，根據題意，列方程組

　　 　　……………………………………………4分

解，得　　　　　　　　　 ………………………………………………6分

∴ A種帳篷400頂，B種帳篷200頂．　　 ………………………………………7分

4.

3. 解：(1)a=2,b=0.125

(2)圖略

(3)設一等獎x人，二等獎y人，依題意得

解得所以他們共獲獎金=50×9+30×20=1050元