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Course by: Nguyễn Hồng Hà. E-mail the author

# bài tập tổ hợp

Module by: Nguyễn Hồng Hà. E-mail the author

COUNTING AND ODERING TECHNIQUES

1.

TRACK MEET AMONG SCHOOLS A , B AND C

 First Place(5 points) Second Place(3 points) Third Place(1 point) Event I A Event II A B Event III C

A partially completed scorecard for a track meet is shown above . Schools A, B and C each entered one person in each of the three events and there were no ties. What is one possible total score for school C (Assume that all points are awarded in each event.)

2. In a stack of six cards , each card is labeled with a different integer 0 through 5. If two cards are selected at random without replacement , what is the probability that their sum will be 3 ?

3. A bag contains a number of pieces of candy of which 78 are red , 24 are brown, and the remainder are yellow . If the probability of selecting a yellow piece of candy from this bag at random is 1/3 , how many yellow pieces of candy are in the bag ?

4. There are 120 red marbles and 80 blue marbles in a bag that contains 200 marbles . If only blue marbles are to be added to the bag so that the probability of randomly drawing a blue marble from the bag becomes 2/3 , how many blue marbles must be added to the bag ?

5. There are 3 roads from Plattsville to Ocean Heights and 4 roads from Ocean Heights to Bay Cove . If Martina drives from Plattsville Bay Cove and back , passes through Ocean Heights in both directions , and does not travel any road twice , how many different routes for the trip are possible.

6. A barrel contains only apples and oranges . There are twice as many apples as oranges . The apples are either red or yellow , and 4 times as many apples are red as are yellow. If one piece of fruit is to be drawn at random from the barrel , what is the probability that the piece drawn will be a yellow apple ?

7. A teacher is to be assigned to teach 5 different courses in 5 different class periods on Mondays. If exactly one course meets each period , how many different assignments of courses to these class periods are possible for Mondays ?

8.

 Quiz Score Number of Students Who Received That Score 0 3 1 6 2 7 3 4

A class of 20 students took a 3-question quiz. The table shows the possible scores on this quiz and the number of students who received each of these scores.If one of the students is picked at random , what is the probability that that student’s quiz score will be greater than 1 ?

9. Of the students in a certain homeroom , 9 are in the school play , 12 are in the orchestra , and 15 are in the choral group . If 5 students participate in exactly 2 of the 3 activities and all other students participate in only 1 activity, how many students are in the homeroom ?

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PDF | EPUB (?)

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#### Definition of a lens

##### Lenses

A lens is a custom view of the content in the repository. You can think of it as a fancy kind of list that will let you see content through the eyes of organizations and people you trust.

##### What is in a lens?

Lens makers point to materials (modules and collections), creating a guide that includes their own comments and descriptive tags about the content.

##### Who can create a lens?

Any individual member, a community, or a respected organization.

##### What are tags?

Tags are descriptors added by lens makers to help label content, attaching a vocabulary that is meaningful in the context of the lens.

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#### Module to:

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| A lens I own (?)

#### Definition of a lens

##### Lenses

A lens is a custom view of the content in the repository. You can think of it as a fancy kind of list that will let you see content through the eyes of organizations and people you trust.

##### What is in a lens?

Lens makers point to materials (modules and collections), creating a guide that includes their own comments and descriptive tags about the content.

##### Who can create a lens?

Any individual member, a community, or a respected organization.

##### What are tags?

Tags are descriptors added by lens makers to help label content, attaching a vocabulary that is meaningful in the context of the lens.

| External bookmarks