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Tutors Answer Your Questions about Permutations (FREE)
Question 56961: Can someone, please, explain why this equation is true?
I intuitively understand why it works for odd n (as combinations with k elements are as many as combinations with n-k elements and they just cancel each other out in the end). But this doesn't explain the equation for even n.
Thanks!
Click here to see answer by stanbon(26297)   |
Question 56961: Can someone, please, explain why this equation is true?
I intuitively understand why it works for odd n (as combinations with k elements are as many as combinations with n-k elements and they just cancel each other out in the end). But this doesn't explain the equation for even n.
Thanks!
Click here to see answer by fanks(6) |
Question 55651This question is from textbook
: I really don't know how to go over this. I am confuse about the linear triplet part.Please explain...Thanks.
DNA (Deoxyribonucleic acid) is made of nucleotides, and each nucleotide can contain any one of these nitrogenous bases: A(Adenine), G (Guanine), C (cytosine), T(thymine). If one of these four bases(A,G,C,T) must be selected three times to form a linear triplet,how many different triplets are possible? Note that all four bases can be selected for each of the three components of the triplet.This question is from textbook
Click here to see answer by fanks(6) |
Question 59433This question is from textbook elementary statistics
: An election committee of three men and four women has been formed to elect a local representative. Each of the seven members must be assigned to investigate one of seven different candidates. How many different ways can those assignments be made?
so do I just plug 4 into the combination formula and then 3, which both give me 35, and then multiply 35*35? do I have todivide that answer into 49 which is the 7 times 7? I am confused.This question is from textbook elementary statistics
Click here to see answer by aaaaaaaa(138) |
Question 59864: I do not understand how to tell when to use combination and when to use permutation. The word problem is: Jack has seven frozen meals in his freezer. How many ways can he choose to have them for dinner Sunday through Saturday?
Click here to see answer by funmath(2873) |
Question 61819: 5 School children, including L & M, will be seated in a row of 5 seats. In how many ways can this be done id L & M must NOT sit together?
I tried 5! (# of ways 5 can sit together) - 4! (if L & M did sit together). Please help.
Click here to see answer by stanbon(26297) |
Question 62971: Richard Stanley writes in his book "Enumerative Combinatorics" that it is easily seen why  where f(n) is the number of subsets of [n] ({1,2,3,..,n}) that do not contain two consecutive integers.
Can someone actually explain why it is so, please?
Thanks!
Click here to see answer by joyofmath(189) |
Question 63104: I hope you can help me with this problem:
A ski trip at the school has been arranged. There are 30 students that have paid for the trip and 6 parnts that have volunteered to chaperone. To transport the students and parents easily they are to be divided into two groups. One group has 10 students and 2 parents, and the other group has 20 students and 4 parents.
A) How many different groups of ten students can be formed?
B) How many diffeent groups consisting of 10 students and 2 parents are posible?
C) Kelly is one of the students going on the trip, and Kelly's mother is a chaperone. Kelly's mother would prefer to be in the smaller group and not in the same group as Kelly. If this wish is honoured, how many ways can the smaller group and its chaperone be chosen?
Click here to see answer by stanbon(26297) |
Question 63762: This was an extra credit question that nobody knew how to answer. We have not covered permutations and could find nothing about it our books. Please help:
How many permutations of the word PRODUCT are there, if all the letters are used without repetition.
Click here to see answer by joyofmath(189) |
Question 64542: Balls numbered 1 to 12 are dropped from the top of a maze, flow thru and land in slot A, B, C and D. In how many ways can the ball land if a)5,3,1,3 balls fall into A, B, C and D b)an equal number of balls fall into each slot and c) two slots are empty and an equal number of balls fall into the other two slots?
I think that part a) 12!/5!3!1!3! and b) 12!/4.3! are these ok? please help with part c.
Click here to see answer by stanbon(26297) |
Question 65320This question is from textbook comrpehensive review
: 1)a commitee of 5 is to be chosen from men and 3 women. what is the probability that the commiteee will include all 4 men?
2) mrs. young teaches 10 boys and 15 girls in her algebra class. she chooses two students at random to work on the blackboard.
a) how many different four member teams are possible?
b)how many of these team will consist of exactly two juniors and two sisters?
c)what is the probability that one of the four member teams will consist of exactly one juniors and three seniors?
d)what is the probability that one four member team will consist of juniors only?This question is from textbook comrpehensive review
Click here to see answer by stanbon(26297) |
Question 65417: Ten teams play a game in which they either win lose or draw. With a key of W=win L=Lose and D= Draw - I suppose the first permutation would be WWWWWWWWWW, perhaps followed by WWWWWWWWWL etc etc. ...What would the total number of permutations be for all ten games. Is it possible to see all the possible permutations for this online?
Click here to see answer by stanbon(26297) |
Question 65519: We had to make a probability game in Gr 12 Data Management. We now have to find out the probability of winning and the expected return. Mine was called Multiples. Here are the rules:
· It costs $2 to play.
· Roll the die.
· If you roll a 1 you win automatically (because all numbers are multiples of 1)
· If you roll any other number then pick the number of cards that corresponds to the number you rolled. (Example: if you roll a 4, choose 4 cards from the deck)
· If all the cards add up to a multiple of the number you rolled then you win your bet back plus $1.
· If all the cards add up to a multiple of the number you rolled, you win your bet back plus $4.
· If your cards do not add to a multiple of the number you rolled, you lose.
I don't get the probability. there must be a million cases because there are so many different sums of 2, 3, 4, 5, 6 you can get with a deck of 52 cards. Please help.
Click here to see answer by venugopalramana(3286)  |
Question 65521: We had to make a probability game in Gr 12 Data Management. We now have to find out the probability of winning and the expected return. Mine was called Multiples. Here are the rules:
· It costs $2 to play.
· ace = 1, jack, queen, king = 10.
· Roll the die.
· If you roll a 1 you win automatically (because all numbers are multiples of 1)
· If you roll any other number then pick the number of cards that corresponds to the number you rolled. (Example: if you roll a 4, choose 4 cards from the deck)
· If all the cards add up to a multiple of the number you rolled then you win your bet back plus $1.
· If all the cards add up to a multiple of the number you rolled, plus the number you rolled is one or more of the cards you selected, you win your bet back plus $4. (Example: if you roll a 4, there would have to be at least one 4 selected out of the 4 cards)
· If your cards do not add to a multiple of the number you rolled, you lose.
I don't get the probability Or the expected return. there must be a million cases because there are so many different sums of 2, 3, 4, 5, 6 you can get with a deck of 52 cards. Please help.:
Click here to see answer by venugopalramana(3286) |
Question 66200: I learned this last year, but I don't remember the formula and I can't find it anywhere. I appreciate any help!!
A store sells 5-cent, 10-cent, and 15-cent pencils. How many different ways can you spend $.45 on pencils?
Click here to see answer by checkley71(8405) |
Question 67160: How many 5 digit numbers can be formed from the numbers 1 to 7 with repeating a number?
There are 15 community members campaigning for seats on the town council. If there are only five open seats, how many different ways can the community members be elected?
Click here to see answer by stanbon(26297) |
Question 70054: Replacement times for new Ford Taurus GL automobiles are normally distributed with a mean of 7.1 years and a standard deviation of 1.4 years. Find the probability that seven randomly selected Taurus GL automobiles will have a mean replacement time greater than 7.0 years.
get z=.071 a=4721 and .5279
Click here to see answer by stanbon(26297) |
Question 70123: Permutations are just an application of fundamental counting principle. Combinations are just a application of Permutations and the counting principle. So would you say that Combinations are also just an application of the counting principle?
Click here to see answer by stanbon(26297) |
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Older solutions: 1..45, 46..90, 91..135, 136..180, 181..225, 226..270, 271..315, 316..360, 361..405, 406..450, 451..495, 496..540, 541..585, 586..630, 631..675, 676..720
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