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习题练习:Counting Principles 

 作者: admin 发布日期: 2024-06-02 22:24   总分: 16分  得分: _____________

答题人: 游客未登录  开始时间: 24年06月02日 22:24  切换到: 整卷模式

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1#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Find the number of ways in which twewcad2er03/zk;1e am:opuv;e zc6b ow ,hk0c7lve different baseball cards can be given to Emily, Harry, John and Olivia, if Emily is to receive 5 cards, Hca 1e;:m crwp /cok0,u3;wked6 a27bvz e0hzoarry is to receive 3 cards, John is to receive 3 cards and Olivia is to receive 1 card.   

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2#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Tyler needs to decide the order in which to schedule 1q(((+a-xisw+ rbht oi1 exams for his school. Two of these exams are Chemistry ( 1 SL and 1 HL). Find the number of different ways Tyler can schedule the 11 exams given that the two Chemistry subi(qx- i asr(h (bo++twjects must not be consecutive.$\approx a \times 10^{b}$ a =    b =   

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3#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A school basketball team of 5 studm :m+e *hcrj)gc31ew 4kpka mgx(cz :-ents is selected from 8 boys and 4 girls.
1. Determine how many possible teams can be chosen.   
2. Determine how many teams can be formed consisting of 3 boys and 2 girls?   
3. Determine how many teams can be formed consisting of at most 3 girls?   

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4#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A police department has 4 male and 7 female officers. A spe;u9 8dbuk1.s*qt9njc1c qunc cial group of 5 officers is to be assembled f ku.uuc ;9b1c1q8 ndqcnt*s 9jor an undercover operation.
1. Determine how many possible groups can be chosen.   
2. Determine how many groups can be formed consisting of 2 males and 3 females.   
3. Determine how many groups can be formed consisting of at least one male.   

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5#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  In an art museum, there are 8 different paintings by Pic3*z ze/ hs ya*uwdhy(g37d;kl asso, 5 different paintings by Van Gogh, and 3 different paintings by Rembrandt. The curator of the museum wants to hold an exhibition in a h klyu*dsh73h/e( 3yaw ;*gzdzall that can only display a maximum of 7 paintings at a time.
The curator wants to include at least two paintings from each artist in the exhibition.
1. Given that 7 paintings will be displayed, determine how many ways they can be selected.   
2. Find the probability that more Rembrandt paintings will be selected than Picasso paintings or Van Gogh paintings.   

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6#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Peter needs to decide the order in which to schedule 14 exams for zw3y3,ei3n ljhis school. Two of these exams are Chemistry ( 1 SL and 1 HL). Find the number of different ways Peter can schedule the 14 exams 3e3,ilznw3 jygiven that the two Chemistry subjects must not be consecutive.$\approx a \times 10^{b}$ a =    b =   

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7#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Ten students are to be arranged in a new chemistryj 0bx+px3n 1wz lab. The chemistry lab is set out in twn p w0zx+1jx3bo rows of five desks as shown in the following diagram.



1. Find the number of ways the ten students may be arranged in the lab.

Two of the students, Hugo and Leo, were noticed to talk to each other during previous lab sessions.   
2. Find the number of ways the students may be arranged if Hugo and Leo must sit so that one is directly behind the other. For example, Dest 1 and Desk 6 .   
3. Find the number of ways the students may be arranged if Hugo and Leo must not sit next to each other in the same row.   

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8#
 
问答题 ( 1.0 分) 切至整卷模式 搜藏此题  
An arts and crafts store is offeri/squcc:r8z 4a ng a special package on personalized keychains. Customers c: ccqsu 8rz4a/an choose to personalize their keychains with up to 3 different charms from a selection of 6 different types of charms.
Determine how many ways a customer can personalize a keychain if
1. The order is important.
2. The order is not important.
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9#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A professor and five of his studen qepsftp7bal:l2h 6sbll93j f4*3tf/ts attend a talk given in a lecture series. They have alljtfpfbfb ha6spe:/742 *9l l qt33s row of 8 seats to themselves.
Find the number of ways the professor and his students can sit if
1. the professor and his students sit together.   
2. the students decide to sit at least one seat apart from their professor.   

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10#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Julie works at a book store and has nine books t m j3x0zs3z(neo display on the main shelf of the store. Four of the books are non-fiction and five are fiction. Each book is different. Determine the number of possible ways Ju3( jzns0zmxe3lie can line up the nine books on the main shelf, given that
1. the non-fiction books should stand together;   
2. the non-fiction books should stand together on either end;   
3. the non-fiction books should stand together and do not stand on either end.   

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11#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Sophia and Zoe compete in a freestyle swimming race where n0lt k)/cho n5there are no tied finishes and there is a total of 10 competitors. Find the total number of possible ways in w/ knnlco) t50hhich the ten swimmers can finish if Zoe finishes
1. in the position immediately after Sophia;   
2. in any position after Sophia.   

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12#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  There are 11 players on a football team who are asked to line upzml 63kip84 nhxn9)z u in one straight line for a team photo. Three of the team members namn 8z zph493)lik nxum6ed Adam, Brad and Chris refuse to stand next to each other. There is no restriction on the order in which the other team members position themselves.
Find the number of different orders in which the 11 team members can be positioned for the photo.   

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13#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  There are six office cubicles arranged in a grid w) fu7 xc.z+a qzgf5 io44ffv+eith two rows and three columns as shown in the following diagram. Aria, Bella, Charlotte, Danna, and Emma are to be stationed inside the cubicles to work on various company pro7cqvxff+izg44f u+)5aezfo .jects.
Find the number of ways of placing the team members in the cubicles in each of the following cases.
1. Each cubicle is large enough to contain the five team members, but Danna and Emma must not be placed in the same cubicle.   
2. Each cubicle may only contain one team member. But Aria and Bella must not be placed in cubicles which share a boundary, as they tend to get distracted by each other.   

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14#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The barcode strings of:rs ebqi7oto.h2 ig31no ij46 a new product are created from four letters $ \mathrm{A}$, $\mathrm{B}$, $\mathrm{C}$, $\mathrm{D}$ and ten digits $0,1,2, \ldots, 9$ . No three of the letters may be written consecutively in a barcode string. There is no restriction on the order in which the numbers can be written. Find the number of different barcode strings that can be created.$\approx a \times 10^{b}$ a =    b =   

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15#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Sophie and Ella play a game. They each haved zd9+uf)hdb79w k q6q five cards showing roman numerals I, V,6) q9qdb kdw7 +9fduzh X, L, C. Sophie lays her cards face up on the table in order I, V, X, L, C as shown in the following diagram.


Ella shuffles her cards and lays them face down on the table. She then turns them over one by one to see if her card matches with Sophie's 4 card directly above. Sophie wins if no matches occur; otherwise Ella wins.
1. Show that the probability that Sophie wins the game is $\frac{11}{30}$ .

Sophie and Ella repeat their game so that they play a total of 90 times. Let the discrete random variable X represent the number of times Sophie wins.   
2. Determine:
1. the mean of X ;   
2. the variance of X .   

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16#
 
问答题 ( 1.0 分) 切至整卷模式 搜藏此题  
Jack and John have decided to play a game. isi9s (:o bc,lThey will be rolling a die seven times. One roll of a die is considered as one round of the game. On each round, John agrees to pay Jack 4 dollcsi9b i,(sl:o ars if 1 or 2 is rolled, Jack agrees to pay John 2 dollars if 3,4,5 or 6 is rolled, and who is paid wins the round. In the end, who earns money wins the game.
1. Show that the probability that Jack wins exactly two rounds is $\frac{224}{729}$ .
2. 1. Explain why the total number of outcomes for the results of the seven rounds is 128 .
2. Expand $(1+y)^{7}$ and choose a suitable value of y to prove that

$128=\binom{7}{0}+\binom{7}{1}+\binom{7}{2}+\binom{7}{3}+\binom{7}{4}+\binom{7}{5}+\binom{7}{6}+\binom{7}{7}$ .

3. Give a meaning of the equality above in the context of the seven rounds.
3. 1. Find the expected amount of money earned by each player in the game.
2. Who is expected to win the game?
3. Is this game fair? Justify your answer.
4. Jack and John have decided to play the game again.
1. Find an expression for the probability that John wins five rounds on the first game and two rounds on the second game. Give your answer in the form

$\binom{7}{r}^{2}\left[\frac{1}{3}\right]^{s}\left[\frac{2}{3}\right]^{t}$

where the values of r, s and t are to be found.
2. Use your answer to (d) (i) and seven similar expressions to write down the probability that John wins a total of seven rounds over two games as the sum of eight probabilities.
3. Hence prove that

$\binom{14}{7}=\sum_{k=0}^{7}\binom{7}{k}^{2}$

5. Now Jack and John roll a die 12 times. Let A denote the number of rounds Jack wins. The expected value of A can be written as

$\mathrm{E}[A]=\sum_{r=0}^{12} r\binom{12}{r}\left[\frac{a^{12-r}}{b^{12}}\right]$

1. Find the value of a and b .
2. Differentiate the expansion of $(1+y)^{12}$ to prove that the expected number of rolls Jack wins is 4 .

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