12. 解：(1)设总厂原来每周制作帐篷千顶，分厂原来每周制作帐篷千顶．

由题意，得······················································································· 3分

解得所以(千顶)，(千顶)．

答：在赶制帐篷的一周内，总厂、分厂各生产帐篷8千顶、6千顶．····························· 6分

(2)设从(甲市)总厂调配千顶帐篷到灾区的地，则总厂调配到灾区地的帐篷为千顶，(乙市)分厂调配到灾区两地的帐篷分别为千顶．

甲、乙两市所需运送帐篷的车辆总数为辆．······························································· 8分

由题意，得．

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

因为，所以随的增大而减小．

所以，当时，有最小值60．

答：从总厂运送到灾区地帐篷8千顶，从分厂运送到灾区两地帐篷分别为1千顶、5千顶时所用车辆最少，最少的车辆为60辆．　　　 12分

11. 解：设生产奥运会标志x套，生产奥运会吉祥物y套．根据题意，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：该厂能生产奥运会标志2000套，生产奥运会吉祥物2400套．……8分

10. (1)甲队行进了2小时，乙队行进了2.5小时．

设乙队的速度为x，则甲队为1.5x + 5．

由题意得方程　 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．

即甲队赶路的速度为50 km∕h，乙队赶路的速度为30 km∕h．

(2)设若由乙队单独施工，需x小时才能完成．

则由题意有 　6×()+ 5.5×= 1．

解得　 x = 11．

即乙队单独做，需要11小时才能完成任务．

9. 解：(1)设小明他们一共了个成人，个学生，

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

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

答：小明他们一共去了7个成人，4个学生．································································ 7分

(2)若按14人购买团体票，则共需(元)

(元)．

购买团体票可省24元．····························································································· 3分

8. 解　 ∵

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

将③代入①，得．解得．代入③，得．

∴原方程组的解为 　　　 6分

7. 解：设生产奥运会标志x套，生产奥运会吉祥物y套，得

解得，答略.

6. .解：设原计划每天挖土石方x万立方米，增调人员和设备后每天挖y万立方米················ 1分

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

　　　 解之得：

　 答：原计划每天挖土石方1.3万立方米，增调人员和设备后每天挖3.6万立方米······ 8分

5.

解：设A种帐篷x顶，B种帐篷y顶，根据题意，列方程组

　　 　　……………………………………………4分

解，得　　　　　　　　　 ………………………………………………6分

∴ A种帐篷400顶，B种帐篷200顶．　　 ………………………………………7分

4.

3. 解：(1)a=2,b=0.125

(2)图略

(3)设一等奖x人，二等奖y人，依题意得

解得所以他们共获奖金=50×9+30×20=1050元