Questions on Algebra: Combinatorics and Permutations answered by real tutors!

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Question 57067: if 18c2r=153*13c2r-5 what is the value of r?
Click here to see answer by tutorcecilia(2152) About Me 

Question 57168: (-48)(-17)=
Click here to see answer by checkley71(8403) About Me 

Question 58680: I don't know how to solve this
I don't understand what this is asking me to do.
Can you show me how to set this up?
P(6,5)

Click here to see answer by checkley71(8403) About Me 

Question 59432: 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?
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Question 59433: 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.

Click here to see answer by aaaaaaaa(138) About Me 

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(2933) About Me 

Question 59891: Find the first five outputs of the following recursively defined function:
f(1)=8,(thats given) f(n+1)=-f(n)+6
its not really a permutation but i didnt know what category to put it in

Click here to see answer by stanbon(75887) About Me 

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(75887) About Me 

Question 62107: can you plaese help and explain if you would like, solve this equation? please
7/x + 1/2 =4

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Question 62106: can you plaese help and explain if you would like, solve this equation? please
7 1
- + - = 4
x 2

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Question 62971: Richard Stanley writes in his book "Enumerative Combinatorics" that it is easily seen why f%28n%29+=+f%28n-1%29%2Bf%28n-2%29 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) About Me 

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(75887) About Me 

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.

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Question 63950: An urn contains 8 white balls and 4 red balls. In how many ways can 4 balls be drawn if
a) 3 balls are white an 1 is red
b) 2 balls are white and 2 are red
c) all four balls are white

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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(75887) About Me 

Question 65318: a bag contains five green marble and three red marbles. if three marbles are chosen at random without replacement, what is the probability that all three will be green?
Click here to see answer by stanbon(75887) About Me 

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(75887) About Me 

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) About Me 

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) About Me 

Question 66198: Karen has forgotten the four-digit code to activate the copying machine. She remembers the digits are 2, 4, 5, and 6. How many possible combinations are there for Karen to try?
Click here to see answer by Nate(3500) About Me 

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(8403) About Me 

Question 66432: how do you know exactly when the problem is a combination or a permutation?
how do you label the problem? ex. 4 super script c 3? how do you solve these?

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Question 66971: When the binomial (2x-3y)^11 is expanded, what is the coefficient of x^8y^^3 taking into consideration the coefficients 2 and -3. Thank you
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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?

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Question 68165: Six people are running a race. How many arrangements of winner, second place, and third place are possible?
A 18
B 36
C 108
D 120

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Question 68166: There are 9 players on a softball team. How many ways can the coach pick the first 5 batters?
A 5
B 45
C 15,120
D 72,876

Click here to see answer by stanbon(75887) About Me 

Question 68461: 3 girls & 4 boys are to be seated in a row containing 7 chairs. If the chairs at both ends of the row must be occupied by girls, in howmany different ways can the children be seated?
Click here to see answer by checkley71(8403) About Me 

Question 68455:













In how many ways can 7 different colors be arranged in a row if the first is always red, the last is always blue and the middle one is always green?

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Question 68971: a= (2, 3, 4) & b= (3,4,5)
solve a u b
A upisde down u b

Click here to see answer by funmath(2933) About Me 

Question 69055: Given the digits 3,9,5,6& 2, howmany different 5 digit numbers reater than 41,000(using each digit once) can form?
Click here to see answer by josmiceli(19441) About Me 

Question 69034: Each Morse code symbol for a letter of the alphabet consists of dots(.) and dashes(-). Each symbol contains between 1 and 4 dots or dashes. How many different symbols can be made.
Click here to see answer by josmiceli(19441) About Me 

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(75887) About Me 

Question 70124: if you invest $100 at the end of each month in a fixed-interest mutual fund paying annual interest of 6% compounded monthly, how much will your investment be worth after 10 yrs?
Click here to see answer by stanbon(75887) About Me 

Question 70126: this term there are eight candidates for three student senate seats, how many different ways can the seats be chosen?
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Question 70125: twelve students are in a class. they are split so that five go to room A, four go to room B and three go to room C. how many different ways can this happen?
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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(75887) About Me 

Question 70262: A die is rolled. The sample space of equally likely outcomes is {1,2,3,4,5,6} find the probability of getting 9
Click here to see answer by checkley75(3666) About Me 

Question 70264: You have six pairs of jeans, three shirts, two pairs of sandles. How many different outfits can you wear from these choices?
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Question 71406: find the number and sum of all the divisor of 840
Click here to see answer by venugopalramana(3286) About Me 

Question 72163: I need help with this problem, it is multiplying and dividing factorials.
In case you cannot tell:
/= Division
*= Multiplication
6!/2!4! * 5!/4!1!
Thank you!

Click here to see answer by checkley75(3666) About Me 
Question 72163: I need help with this problem, it is multiplying and dividing factorials.
In case you cannot tell:
/= Division
*= Multiplication
6!/2!4! * 5!/4!1!
Thank you!

Click here to see answer by jim_thompson5910(35256) About Me 

Question 72454: Determine the constant term in the expansion of (2x-2/5x^2)^8.
I am doing this math independently. I have looked through my textbooks, but cannot find what a consant term is. I have expanded this by binomial expansion but there is not one constant term in the solution as all constants are differnt numbers with differnt x values.
Thank you
Kristen

Click here to see answer by Edwin McCravy(20054) About Me 

Question 72460: Determine the coefficent of the term containing a^5 in the expansion of
(a - 1/a)^5

I got 1 for the coefficent of a^5. However, I can not read my teachers writing and I think that the the question could be, "Determine the coefficent of the term containing a in the expansion of (a - 1/a)^5". If this is the case I am not sure of the coefficent since there are two a's and when you expand using binomial expansion, there are two possible terms that have a values (either multipy the a's together to get a or there is just an a in one of the terms).
Thank you,
Kristen

Click here to see answer by stanbon(75887) About Me 

Question 72458: Determine the eight term (simplified) in the expansion of (4a+7b)^15.
Thank you
Kristen

Click here to see answer by stanbon(75887) About Me 

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, 721..765, 766..810, 811..855, 856..900, 901..945, 946..990, 991..1035, 1036..1080, 1081..1125, 1126..1170, 1171..1215, 1216..1260, 1261..1305, 1306..1350, 1351..1395, 1396..1440, 1441..1485, 1486..1530, 1531..1575, 1576..1620, 1621..1665, 1666..1710, 1711..1755, 1756..1800, 1801..1845, 1846..1890, 1891..1935, 1936..1980, 1981..2025, 2026..2070, 2071..2115, 2116..2160, 2161..2205, 2206..2250, 2251..2295, 2296..2340, 2341..2385, 2386..2430, 2431..2475, 2476..2520, 2521..2565, 2566..2610, 2611..2655, 2656..2700, 2701..2745, 2746..2790, 2791..2835, 2836..2880, 2881..2925, 2926..2970, 2971..3015, 3016..3060, 3061..3105, 3106..3150, 3151..3195, 3196..3240, 3241..3285, 3286..3330, 3331..3375, 3376..3420, 3421..3465, 3466..3510, 3511..3555, 3556..3600, 3601..3645, 3646..3690, 3691..3735, 3736..3780, 3781..3825, 3826..3870, 3871..3915, 3916..3960, 3961..4005, 4006..4050, 4051..4095, 4096..4140, 4141..4185, 4186..4230, 4231..4275, 4276..4320, 4321..4365, 4366..4410, 4411..4455, 4456..4500, 4501..4545, 4546..4590, 4591..4635, 4636..4680, 4681..4725, 4726..4770, 4771..4815, 4816..4860, 4861..4905, 4906..4950, 4951..4995, 4996..5040, 5041..5085, 5086..5130, 5131..5175, 5176..5220, 5221..5265, 5266..5310, 5311..5355, 5356..5400, 5401..5445, 5446..5490, 5491..5535, 5536..5580, 5581..5625, 5626..5670, 5671..5715, 5716..5760, 5761..5805, 5806..5850, 5851..5895, 5896..5940, 5941..5985, 5986..6030, 6031..6075, 6076..6120, 6121..6165, 6166..6210, 6211..6255, 6256..6300, 6301..6345, 6346..6390, 6391..6435, 6436..6480, 6481..6525, 6526..6570, 6571..6615, 6616..6660, 6661..6705, 6706..6750, 6751..6795, 6796..6840, 6841..6885, 6886..6930, 6931..6975, 6976..7020, 7021..7065, 7066..7110, 7111..7155, 7156..7200, 7201..7245, 7246..7290, 7291..7335, 7336..7380, 7381..7425, 7426..7470, 7471..7515, 7516..7560, 7561..7605, 7606..7650, 7651..7695, 7696..7740, 7741..7785, 7786..7830, 7831..7875, 7876..7920, 7921..7965, 7966..8010, 8011..8055, 8056..8100, 8101..8145, 8146..8190, 8191..8235, 8236..8280, 8281..8325, 8326..8370, 8371..8415, 8416..8460, 8461..8505, 8506..8550, 8551..8595, 8596..8640, 8641..8685, 8686..8730, 8731..8775, 8776..8820, 8821..8865, 8866..8910, 8911..8955, 8956..9000, 9001..9045, 9046..9090, 9091..9135, 9136..9180, 9181..9225, 9226..9270, 9271..9315, 9316..9360, 9361..9405, 9406..9450, 9451..9495, 9496..9540, 9541..9585, 9586..9630, 9631..9675, 9676..9720, 9721..9765, 9766..9810, 9811..9855, 9856..9900, 9901..9945, 9946..9990, 9991..10035