20. [解] 设这个月的石油价格相对上个月的增长率为.根据题意,得
.解得:.
答:这个月的石油价格相对上个月的增长率为.
19. (1)设该农机服务队有技术员工人、辅助员工人,
则,解得.
该农机服务队有技术员工10人、辅助员工5人.
(2)由,得.
,,
并且都是100的整数倍,
,,.
本次奖金发放的具体方案有3种:
方案一:技术员工每人1600元、辅助员工每人800元;
方案二:技术员工每人1500元、辅助员工每人1000元;
方案三:技术员工每人1400元、辅助员工每人1200元.
18.
2.(2008山东济南)解方程:2(x-1)+1=0.
解:2x-2+1=0……1分
2x=1……1分
X=……3分
17. 解(1)设2007职业中专的在校生为x 万 人
根据题意得:1500×1.2x -1500x =600 ··························································· 3分
解得: ··············································· 5分
所以.
···························································································· 7分
答:略. ············································ 8分
16.
解:方案一获利:4×2000+6×500=11000(元)
方案二:设制奶粉x天,则
1×x+(4-x)×3=10,
得x=1(天)
故1×1×2000+3×3×1200=12800(元)
选方案二.
15. 解:设老师捐款x元,学生捐款y元.则有
解得
答:该校老师捐款18000元,学生捐款27000元.
14. 解:(1)设每条成衣生产线和童装生产线平均每天生产帐篷各x、y顶,则
,
解得x=41,y=32.
答:每条成衣生产线平均每天生产帐篷41顶,每条童装生产线平均每天生产帐篷32顶.
(2)由3(4×41+5×32)=972<1000知,即使工厂满负荷全面转产,还不能如期完成任务.
可以从加班生产、改进技术等方面进一步挖掘生产潜力,或者动员其它厂家支援等,想法尽早完成生产任务,为灾区人民多做贡献.
13. 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
可列出方程组:
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
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