Math (combination/permutation)
posted by Cynthia .
Question 1:
There are 12 students in a class. Find the number of ways that 12 studenets can take 3 different tests if 4 students are to take each test.
Question 2
Find the number of ways 12 students can be partitioned into 3 teams A, B, C, so that each team contain 4 students.
I don't get what is the difference between the two. For the first one, the book uses C(12,4) * C(8,4) = 34650. I use the permutation method, which is bascially the same 12!/(4!4!4!) = 34650
For the second question, the books tells me to think that A is in team A and you have to chose three different people to join team A, resulting into C(12,3). The same logic applies to team B: C(7,3) and that left 4 for team C.
Therefore the answer was C(12,3) * C(7,3) = 5925.
THe book tells me if you use the partition method, all you do is 34650/6 = 5925 because 3! is an ordered partition. (what is an ordered partition anyway?)
Respond to this Question
Similar Questions

Math
Ok, so my math teacher didn't tell us ways to do this faster, and it's late enough as it is so I don't want to be up all night doing homework. D; *Note: A permutation is where the order matters. A combination is where it doesn't. Find … 
math
Create two problems for your fellow students to solve. Make one of the questions a permutation and the other one a combination. The permutation I gave this example. In how many ways can we arrange 8 movies on a book self? 
Math (combination/permutation)
Question 1: There are 12 students in a class. Find the number of ways that 12 studenets can take 3 different tests if 4 students are to take each test. Question 2 Find the number of ways 12 students can be partitioned into 3 teams … 
Maths(permutation)
A teacher prepares 5 different books for 7 students.If each student can get one or no book from the teacher , find the number of ways of distributing the books among the students. can u explain it to me detailly.i have thought about … 
Math
How many ways can 3 students be chosen from a class of 20 to represent their class at a banquet? 
math help me
Solve: 6C3 (1 point) 120 720 20 240 2. Which is not a combination? 
Probability/Statistics
The teacher of a mathematics class has written up the final exam, but wants the questions to be random for each student. There are 28 students in the class, and the test has 100 questions. Each question has four possible answers. a. … 
math
The teacher of a mathematics class has written up the final exam, but wants the questions to be random for each student. There are 28 students in the class, and the test has 100 questions. Each question has four possible answers. a. … 
Probability/Statistics
The teacher of a mathematics class has written up the final exam, but wants the questions to be random for each student. There are 28 students in the class, and the test has 100 questions. Each question has four possible answers. a. … 
Algebra
2. Which is not a combination? choosing 3 toppings for your pizza lining 3 students up in a row choosing 2 desserts from a tray of 10  Choosing 5 students to represent a class of 30 3. How many ways can you choose 3 dishes from