利润问题

发布时间:2012-04-05   来源:文档文库   
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利润问题
利润的百分数=(卖价-成本)÷成本×100 卖价=成本×1+利润的百分数) 成本=卖价÷1+利润的百分数) 商品的定价按照期望的利润来确定 定价=成本×1+期望利润的百分数) 卖出价=定价×折扣 利润率=利润÷售价=(售价-成本)÷成本 毛利率=(售价-进价)÷进价×100 银行存取款利息 利息=本金×利率×期数 含税价格=不含税价格×1+增值税税率)
商店出售商品,总是期望获得利润.例如某商品买入价(成本50元,以7070-50=20(.20÷50=0.4=40%,我们也可以说获得 40%的利润.因此 利润的百分数=(卖价-成本÷成本×100%. 卖价=成本×(1+利润的百分数. 成本=卖价÷(1+利润的百分数. 商品的定价按照期望的利润来确定. 定价=成本×(1+期望利润的百分数. 定价高了,商品可能卖不掉,只能降低利润(甚至亏本,减价出售.减价有时也按定价的百分数来算,这就是打折扣.减价 25%,就是按定价的(1-25%= 75%出售,通常就称为75.因此 卖价=定价×折扣的百分数. 1 某商品按定价的 80%(八折或 80出售,仍能获得20%的利润,定价时期望的利润百分数是多少? 解:设定价是“1”,卖价是定价的 80%,就是0.8.因为获得20% 定价的期望利润的百分数是 答:期望利润的百分数是50%. 2 某商店进了一批笔记本, 30%的利润定价.当售出这批笔记本的 80%后,为了尽早销完,商店把这批笔记本按定价的一半出售.问销完后商店实际获得的利润百分数是多少? 解:设这批笔记本的成本是“1”.因此定价是(1+ 30%=1.3.其中 80%的卖价是 1.3×80% 20%的卖价是 1.3÷20%. 因此全部卖价是 1.3×80% +1.3 ÷20%= 1.17. 实际获得利润的百分数是
1.17-1= 0.17=17%. 答:这批笔记本商店实际获得利润是 17%. 3 有一种商品,甲店进货价(成本比乙店进货价便宜 10%.甲店按 20%利润来定价,乙店按 15%的利润来定价,甲店的定价比乙店的定价便宜 11.2.问甲店的进货价是多少元? 解:设乙店的进货价是“1”,甲店的进货价就是0.9. 乙店的定价是 (1+ 15%,甲店的定价就是 0.9×(1+20%. 因此乙店的进货价是 11.2÷(1.15- 0.9×1.2=160(.
甲店的进货价是 160× 0.9= 144(. 答:甲店的进货价是144. 设乙店进货价是1,比设甲店进货价是1,计算要方便些. [标签:六年级 奥数 题目 经济问题] 4 开明出版社出版的某种书,今年每册书的成本比去年增加 10%,但是仍保持原售价,因此每本利润下降了40%那么今年这种书的成本在售价中所占的百分数是多少? 解:设去年的利润是“1”.
利润下降了40%,转变成去年成本的 10%,因此去年成本是 40%÷10%= 4. 在售价中,去年成本占 因此今年占 80%×(1+10%= 88%. 答:今年书的成本在售价中占88%. 因为是利润的变化,所以设去年利润是1,便于衡量,使计算较简捷. 5 一批商品,按期望获得 50%的利润来定价.结果只销掉 70%的商品.尽早销掉剩下的商品,商店决定按定价打折扣销售.这样所获得的全部利润,是原来的期望利润的82%,问:打了多少折扣? 解:设商品的成本是“1”.原来希望获得利润0.5. 现在出售 70%商品已获得利润 0.5×70%= 0.35. 剩下的 30%商品将要获得利润 0.5×82%-0.35=0.06. 因此这剩下30%商品的售价是 30%+ 0.06= 0.36. 原来定价是 30%×(1+50%=0.45. 因此所打的折扣百分数是 0.36÷0.45=80%. 答:剩下商品打8折出售. 从例1至例5,解题开始都设“1”,这是基本技巧.设什么是“1”,很有讲究.希望读者从中能有所体会. 6 某商品按定价出售,每个可以获得45元钱的利润.现在按定价打85出售8个,所能获得的利润,与按定价每个减价35元出售12个所能获得的利润一样.问这一商品每个定价是多少元? 解:按定价每个可以获得利润45元,现每个减价35元出售12个,共可获得利润
(45-35×12=120(. 出售8个也能获得同样利润,每个要获得利润 120÷8=15(. 不打折扣每个可以获得利润45元,打85折每个可以获得利润15元,因此每个商品的定价是 (45-15÷(1-85%=200(. 答:每个商品的定价是200. 7 张先生向商店订购某一商品,共订购60件,每件定价100. 张先生对商店经理说:如果你肯减价,每件商品每减价1元,我就多订购3.”商店经理算了一下,如果差价 4%,由于张先生多订购,仍可获得原来一样多的总利润.问这种商品的成本是多少? 解:减价4%,按照定价来说,每件商品售价下降了100×4%=4(.因此张
先生要多订购 3=12(. 由于60件每件减价 4元,就少获得利润 60= 240(. 这要由多订购的12件所获得的利润来弥补,因此多订购的12件,每件要获得利润 240÷12=20(. 这种商品每件成本是 100-4-20=76 (. 答:这种商品每件成本76. 五、间隔发车问题。空间理解稍显困难,证明过程对快速解题没有帮助。一旦掌握了3个基本公式,一般问题都可以迎刃而解。
(1在班车里。即柳卡问题。不用基本公式解决,快速的解法是直接画时间-距离图,再画上密密麻麻的交叉线,按要求数交点个数即可完成。如果不画图,单凭想象似乎对于像我这样的一般人儿来说不容易。
例题:AB是公共汽车的两个车站,从A站到B站是上坡路。每天上午8点到11点从AB两站每隔30分同时相向发出一辆公共汽车。已知从A站到B站单程需要105分钟,从B站到A站单程需要80分钟。问830900A站发车的司机分别能看到几辆从B站开来的汽车? (2在班车外。联立3个基本公式好使。 汽车间距=(汽车速度+行人速度×相遇事件时间间隔------1 汽车间距=(汽车速度-行人速度×追及事件时间间隔------2 汽车间距=汽车速度×汽车发车时间间隔------3 12合并理解,即 汽车间距=相对速度×时间间隔
分为2个小题型:1、一般间隔发车问题。用3个公式迅速作答;2、求到达目的地后相遇和追及的公共汽车的辆数。标准方法是:画图-尽可能多的列3好使公式-结合s全程=v×t-结合植树问题数数。
例题:小峰在骑自行车去小宝家聚会的路上注意到,每隔9分钟就有一辆公交车从后方超越小峰。小峰骑车到半路车坏了,于是只好坐出租车去小宝家。时小峰又发现出租车也是每隔9分钟超越一辆公交车,已知出租车的速度是小峰骑车速度的5倍,如果这3种车辆在行驶过程中都保持匀速,那么公交车站每隔多少分钟发一辆车? 六、平均速度问题。相对容易的题型。大公式要牢牢记住:总路程=平均速×总时间。用s=v×t写出相应的比要比直接写比例式好理解并且规范,形成行程问题的统一解决方案。
七、环形问题。是一类有挑战性和难度的题型,分为同一路径不同路真实相遇能否看到等小题型。其中涉及到周期问题、几何位置问题(题不仔细容易漏掉多种位置可能、不等式问题(针对能否看到问题,即问甲能否在线段的拐角处看到乙。仍旧属于就题论题范畴,不展开了。
八、钟表问题。是环形问题的特定引申。基本关系式:v分针= 12v时针 (1总结记忆:时针每分钟走1/12格,0.5°;分针每分钟走1格,。时针和分针天共重合11次,成直线共11次,成直角共22(都在什么位置需要自己拿表画图总结
(2基本解题思路:路程差思路。即 格或角(分针=格或角(时针+格或角(
格:x=x/12+(开始时落后时针的格+终止时超过时针的格 角:6x=x/2+(开始时落后时针的角度+终止时超过时针的角度

可以解决大部分时针问题的题型,包括重合、成直角、成直线、成任意角度、在哪两个格中间,和哪一个时刻形成多少角度。
例题:在923分时,时针和分针的夹角是多少度?从这一时刻开始,经过多少分钟,时针和分针第一次垂直? (3坏钟问题。所用到的解决方法已经不是行程问题了,变成比例问题了,有相应的比例公式。这里不做讨论了,我也讨论不好,都是考公务员的题型,有难度。 九、自动扶梯问题。仍然用基本关系式s扶梯级数=(v人速度±v扶梯速度×t上或下解决最漂亮。这里的路程单位全部是,唯一要注意的是t上或下要表示成实际走的级数/人的速度。可以PK掉绝大部分自动扶梯问题。
例题:商场的自动扶梯以匀速由下往上行驶,两个孩子在行驶的扶梯上上下走动,女孩由下向上走,男孩由上向下走,结果女孩走了40级到达楼上,男孩走了80级到达楼下。如果男孩单位时间内走的扶梯级数是女孩的2倍,则当该扶梯静止时,可看到的扶梯梯级有多少级? 十、十字路口问题。即在不同方向上的行程问题。没有特殊的解题技巧,只要老老实实把图画对,再通过几何分析就可以解决。
十一、校车问题。就是这样一类题:队伍多,校车少,校车来回接送,队伍不断步行和坐车,最终同时到达目的地(即到达目的地的最短时间,不要求证明4种小题型:根据校车速度(来回不同、班级速度(不同班不同速、班数是否变化分类。
(1车速不变-班速不变-班数2(最常见 (2车速不变-班速不变-班数多个 (3车速不变-班速变-班数2 (4车速变-班速不变-班数2
标准解法:画图-3个式子:1、总时间=一个队伍坐车的时间+这个队伍步行的时间;2班车走的总路程;3一个队伍步行的时间=班车同时出发后回来接它的时间。最后会得到几个路程段的比值,再根据所求代数即可。此类问题可以得到几个公式,但实话说公式无法记忆,因为相对复杂,只能临考时抱佛脚还管点儿用。孩子有兴趣推导一下倒可以,不要死记硬背。
简单例题:甲班与乙班学生同时从学校出发去15千米外的公园游玩,甲、乙两班的步行速度都是每小时4千米。学校有一辆汽车,它的速度是每小时48千米,这辆汽车恰好能坐一个班的学生。为了使两班学生在最短时间内到达公园,那么甲班学生与乙班学生需要步行的距离是多少千米? 十二、保证往返类。简单例题:AB两人要到沙漠中探险,他们每天向沙漠深处走20千米,已知每人最多可以携带一个人24天的食物和水。如果不准将部分食物存放于途中,其中一个人最远可深入沙漠多少千米(要求两人返回出发?这类问题其实属于智能应用题类。建议推导后记忆结论,以便考试快速作答。每人可以带够t天的食物,最远可以走的时间T (1返回类。(保证一个人走的最远,所有人都要活着回来
1、两人:如果中途不放食物:T=2/3t;如果中途放食物:T=3/4t 2、多人:没搞明白,建议高手补充。
(2穿沙漠类(保证一个人穿过沙漠不回来了,其他人都要活着回来共有n(包括穿沙漠者即多人助1人穿沙漠类。 1、中途不放食物:T≤[2n/(n+1tT是穿沙漠需要的天数。 2、中途放食物:T=(1+1/3+1/5+1/7+…+1/(2n-1×t


一、找出划线部分读音与众不同的单词。(10

( 1. A. big B. six C. nice D. miss ( 2. A. work B. wall C. whose D. watch ( 3. A. sorry B. brother C. some D. does ( 4. A. yesterday B. family C. day D. Monday ( 5. A. hear B. pear C. ear D. near ( 6. A. map B. stamp C. face D. cat ( 7. A. three B. those C. their D. these ( 8. A. food B. foot C. book D. good ( 9. A. not B. no C. ink D. ant ( 10.A. names B. apples C. faces D. balls 二、请你按要求完成下列各题。(10
I 1. shoes(单数 __________ 2. bus(复数 __________ 3. don't(完全形式 __________ 4. me(主格 __________ 5. too(同音词 __________ 6. he(物主代词 __________ 7. 努力工作(译成英语 __________ 8. let us(缩写形式 __________ 9. short(反义词 __________ 10. over there(汉语意思__________ II)翻译下面的短语
1. 二瓶果汁 ___________ 2. 到这来 ___________ 3. 在树下 ___________ 4. 双胞胎兄弟 ___________ 5. how much ___________ 6. thanks a lot ___________ 7. look after ___________ 8. put on
___________ 9. 在天空中 ___________ 10. 穿红衣服的女孩 ___________ 三、根据题意,用所给词的适当形式填空。(10 1. Can I have ______(a orange? 2. She _____(like to play the flute. 3. He _____(have got a skipping rope. 4. Please give _____(I a cup of tea.
5. Let's go _____(shop with my mother! 6. Da Ming comes from Chinahe is _____(China.
7. How many _____(hour are there in a day?
8. Lucy _____(look like her father. 9. "Here you are. ""_____(thank."
10. She ______(watch TV every evening. 四、根据提供的情景,选择正确的句子,将其标号填在题前的括号内。(8 A. Let's go to the zoo. B. Can you spell "window"? C. Good evening Dad. D. Good night. E. This is Mr Zhang. F. Look at the new car. G. Come and sit here. H. It's my favourite colour. ( 1. 傍晚见到父亲说:___________ ( 2. 你想说这是我最喜欢的颜色:________ ( 3. 你想叫人拼写窗户这个单词,可以说:_________ ( 4. 你叫汤姆过来坐,可以说:________ ( 5. 你想请别人欣赏这辆红色法拉利小轿车,可以说:_______ ( 6. 想邀请别人一起去动物园,可以说:________ ( 7. 睡前对母亲说晚安,应表达为:________ ( 8. 你向Helen介绍一下张老师,应该说:______ 五、选择填空。(30
( 1. What's this in English? _____ a jeep. A. This is B. That's C. It's D. it is (
2. Where's the bag? A. It's in the car. B. They are here. C. There are. D. Here are. (
3. What's that man? A. He's my brother. B. Yeshe is. C. She's a teacher. D. He's a teacher. (
4. It's _____ my new car. A. / B. a C. is D. isn't (
5. ____ a cat. A. This B. This's C. This is D. That ( 6. Look ____ the nice car. A. to B. and C. at D. in (
7. It's nine o'clock. I must ______. A. go home B. go to home C. to go home
D. go the home
( 8. _____ you see the blackboard? A. Do B. Are C. Is D. Can ( 9. Please give ____ a cup of tea. A. she B. he C. I D. him ( 10. It's time ____ play games. A. in B. on C. for D. to ( 11. The man _______ the photo is my father. A. in B. on the C. in the D. under (
12. _____ name is Mike. A. I B. My C. Me D. mine ( 13. Who is the _____? He is my uncle. A. boy B. man C. woman D. girl (
14. _____ you like this jacket? A. Are B. Do C. Can D. What ( 15. ______ is my umbrella? It's over there. A. Where B. What C. Whose D. how ( 16. What's that ____ English? A. for B. in C. on D. under (
17. Look! The cat is _______. A. walk B. run C. ran D. running (
18. Whose gloves are they? ____ my _____. A. It'smother's B. They'remother's C. They'remother D. It'smother ( 19. The boys are from Tokyo. They are ______. A. China B. English C. Japanese D. Chinese ( 20. There are _____ on the table. A. two bottles of milk
B. two bottles milk C. two bottles of milks D. two bottle of milk ( 21. "Can I help you?""I'd like ______ bags of rice. " A. some B. a C. little D. one ( 22. "What would you like?""I'd like _____ to eat." A. something B. apple C. meat
D. some orange
( 23. Look! Some meat ____ in the box. Some apples _____ in the basket. A. areare B. isis C. areis D. isare (
24. I would like ________. A. some banana B. eat some bananas C. some bananas eat D. some bananas ( 25. Please give me two bottles of _______. A. milk B. waters C. milks D. oranges ( 26. Wellwould you like _____ to drink? A. some thing B. anything C. some things D. something (
27. ____ would you like _____ breakfast? A. Whatwith B. Whatfor C. Whatat D. Howfor (
28. I want some A. meats B. waters C. cakes D. breads (
29. What about __________? A. something to eat B. to eat something C. something eat D. eat something ( 30. "Do you want _____ orange?""NoI'd like _____ bottle of orange." A. aan B. anan C. thean D. ana 六、从Ⅱ栏中选出能对Ⅰ栏中的句子做出正确反应的应答语。(18 I
( 1. Don't be late again. A. A new watch. ( 2. May I have a cup of tea? B. Metoo. ( 3. I like the red fan. C. I see. ( 4. What's that on the desk?
D. Sure. ( 5. Where's Dad? E. Perhaps he's in the study. ( 6. Shall we go to the zoo by bike? F. It's Bob'sI think. ( 7. Whose kite is this? G. Good idea. ( 8. Can I have a look at your dress? H. Yes. Here you are. II
( 1. Could you help me please?
A. OK. ( 2. Thanks a lot. B. You're welcome. ( 3. Let's put the books in the box. C. It's Monday. ( 4. Can you carry it? D. Noit's full.
( 5. Who's on duty today?
E. lam. ( 6. Is it empty? F. Noit's light. ( 7. What day is it today? G. Certainly. ( 8. Is that bag heavy? H. No. Li Lei isn't here. ( 9. Are we all here today? I. Nothanks. ( 10. Let me help you. J. YesI can. 七、在下列各句ABC中找出与划线部分意义相近的词或句子。14分) ( 1. Wang Hai does well in English. A. likes B. is good at C. is writing (
2. I'd like some melons. A. I want B. I like C. I need (
3. Let me see. A. look at B. watch C. think over ( 4. How does she go there? A. get up B. do C. get ( 5. We have three lessons this afternoon. A. texts B. glasses C. classes ( 6. We'll go and get some bananas. A. sell B. want
C. buy (
7. A: It's hot inside. Please open the window. B: Pardon? A. Please say it again. B. I'm sorry. C. All right. (
8. Where are you from? I'm from China. A. I'm from Chinese. B. I'm Chinese. C. I'm in China. (
9. Tom! This is my uncle. A. my father's brother. B. my mother's sister. C. my father's sister. ( 10. What's the time? It's a quarter to one. A. 1:15 B. 1:45 C. 12:45 ( 11. What's the weather like in Shanghai? A. What's the weather in Shanghai? B. How is the weather like in Shanghai?
C. How is the weather in Shanghai?
( 12. Can I play the video games now? I'm afraid you can't. A. You're welcome. B. That's OK. C. Please don't. (
13. We're going to the cinema. A. We're going to do it. B. We're walking in the cinema

C. We're going to see a film. ( 14. Our teacher walks to school on foot every day.
A. Our teacher goes to school on foot every day. B. Our teacher works every day. C. Our teacher likes walking every day. 八、连词成句,注意大小写和标点符号。(10 1. thingsinarethenowthecar ____________________________________________ 2. youwhatwrongiswith ____________________________________________ 3. youlethelpme ____________________________________________ 4. isthewhatweathertodaylike ____________________________________________ 5. youmepleasecouldhelp ____________________________________________ 6. arewhattheycolour ____________________________________________ 7. manyminuteshourtherehowareinan ____________________________________________ 8. himgivepleasewateraofbottle ____________________________________________ 9. toIputtheballintheboxwant ____________________________________________ 10. foxwolffriendsandare ___________________________________________ 九、选择正确答案。(10
Jack is a teacher of English. He is not youngbut he is not old. He has a round
face and black hair. He is tall. There are fifty students in his class. They all like him. Now it's in the afternoon. Looksome students are working in the classroom. Jack is theretoo. He is helping them to study English. He is a good teacherand he is a good friend of them all. (
1. What does Jack do? A. He is a worker. B. He is a teacher. C. He is a doctor. D. He's a nurse. (
2. What colour is his hair? A. It's black. B. His heir is white. C. It is brown. D. He has yellow hair. (
3. How many students are there in his class? A. There are fifteen students in his class. B. There's fifty. C. He has fifty. D. There're fifty in it. ( 4. Jack is a good teacherisn't he? A. Yeshe isn't. B. Nohe is. C. Yeshe's. D. Yeshe is. ( 5. What are the students doing in the classroom? A. They are walking there. B. They are doing their lessons. C. They are helping their teacher. D. They are good friends of Jack.


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