Recent questions tagged permutation-and-combination

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1

Arrangement Problem
The number of ways, we can arrange 5 books in 3 shelves ________. Given answer 2520 n=3 r=5 so answer is 3-1+5 P5= 7p5= 2520 My answer 3*3*3*3*3= 243 Where am I doing wrong? please help

asked Jan 29 in Combinatory by Mayank Bansal (75 points) | 53 views

+1 vote

3 answers

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MadeEasy Subject Test 2019: Combinatory - Permutations And Combinations
Q.The number of ways, we can arrange 5 books in 3 shelves ________.

asked Jan 28 in Combinatory by Badayayash Junior (977 points) | 420 views

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3

Permutation
The number of ways can 5 letter be put into 3 letter boxes A, B, C if letter box A must contain atleast 2 letters ________. Please tell what are the extra cases in this: Choose 2 letters and put in box A – $^5C_2$ Now remaining 3 letters have $3^3$ choices So, $^5C_2 \times 3^3 = 270$

asked Jan 27 in Numerical Ability by shreyansh jain Active (2.2k points) | 147 views

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2 answers

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MadeEasy Full Length Test 2019: Combinatory - Permutations And Combinations
The number of ways 5 letter be put in 3 letter boxes A,B,C. If letter box A must contain at least 2 letters.

asked Jan 22 in Combinatory by snaily16 (245 points) | 207 views

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1 answer

5

MadeEasy Test Series: Combinatory - Permutations And Combinations
why is my approach giving wrong answer: choose 2 men from 8: 8C2 choose 3 women from 5: 5C3 rest 8 people left ( 8+5- 5= 8) , choose 1 from these 8 people = 8C1 Hence after multiplying above three we get 4480 but answer given is 700

asked Jan 22 in Mathematical Logic by bts1jimin (199 points) | 38 views

+1 vote

0 answers

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Made Easy Test Series 2019: Combinatory - Permutations And Combinations
in how many ways 6 letters can be placed in 6 envelopes such that at least 4 letters go into their corresponding envelopes ?

asked Jan 19 in Combinatory by ronin_codex (11 points) | 179 views

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1 answer

7

generating function

asked Jan 15 in Combinatory by Rahul_Rathod_ (425 points) | 103 views

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1 answer

8

#combinatorics
How many ways the letters of the word “AABCCD” can be arranged such that, these neither begin with ‘A’ nor end with D ?

asked Jan 15 in Combinatory by Satbir Boss (21.6k points) | 71 views

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1 answer

9

RRB ALP
No. of ways to arrange the word letters “SEEDING” such that all vowel together Are? 340 360 720 780

asked Jan 14 in Numerical Ability by bhanu kumar 1 Junior (857 points) | 86 views

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0 answers

10

Permutation and combination
In how many different ways can a set of 3n elements be partitioned into 3 subsets of equal number of elements? Isn't this case of distributing distinguishable objects and distinguishable boxes, so the answer should be $(3n)! / ((n!)^3 )$. But ... Can anybody explain? Or post a link where to study all concepts of permutation and combination and counting

asked Jan 12 in Mathematical Logic by bts1jimin (199 points) | 70 views

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1 answer

11

Permutation and Combination
The number of ways can 5 letters be put into 3 letter boxes A,B,C. If letter box A must contain atleast 2 letters ?

asked Jan 12 in Mathematical Logic by Na462 Loyal (6.9k points) | 202 views

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12

Finding the coefficient
What is its answer ?

asked Jan 9 in Combinatory by Nandkishor3939 Active (1.3k points) | 28 views

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0 answers

13

No of subsequence
I understand that number of subsequences for a string of length n is 2^n when we don’t have any repetition. What is the number of “unique” subsequence when we have repetitions. As in the string : aabbbccddd

asked Jan 8 in Algorithms by shaz (369 points) | 79 views

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1 answer

14

MadeEasy Test Series: Numerical Abilty - Permutations and Combinations
Assume that there are 6 color letters L1,L2,L3,L4,L5,L6 are to be placed in 6 same color envelope E1,E2,E3,E4,E5,E6(one letter for each envelop). The number of possibilities to place exactly one letter in the correct envelop______. a)264 b)265 c)455 d)466

asked Jan 7 in Numerical Ability by Nandkishor3939 Active (1.3k points) | 110 views

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1 answer

15

Ace academy test series
Ans:C. Please explain

asked Dec 28, 2018 in Combinatory by amitqy Active (1.8k points) | 136 views

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1 answer

16

NTA NET DEC 18 Q 94

asked Dec 25, 2018 in Combinatory by Sanjay Sharma Boss (48.8k points) | 128 views

+7 votes

6 answers

17

TIFR2019-B-13
A row of $10$ houses has to be painted using the colours red, blue, and green so that each house is a single colour, and any house that is immediately to the right of a red or a blue house must be green. How many ways are there to paint the houses? $199$ $683$ $1365$ $3^{10}-2^{10}$ $3^{10}$

asked Dec 18, 2018 in Combinatory by Arjun Veteran (425k points) | 557 views

0 votes

0 answers

18

Generating function(Find Coefficient of x^100)
How to find coefficient of $x^{100}$? $ = (1+x^{10}+(x^{10})^2 + \dots)(1+x^{20}+(x^{20})^2 + \dots)(1+x^{50}+(x^{50})^2 + \dots)\\ = (\frac{1}{1-x^{10}}).(\frac{1}{1-x^{20}}).(\frac{1}{1-x^{50}}) $

asked Dec 3, 2018 in Combinatory by !KARAN Active (2.2k points) | 165 views

0 votes

1 answer

19

Counting MadeEasy

asked Dec 2, 2018 in Combinatory by garimanand Active (1.6k points) | 73 views

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0 answers

20

Testbook Test Series: Combinatory - Permutations And Combinations
In how many ways we can wear 4 distinct rings in 3 particular fingers?

asked Nov 30, 2018 in Combinatory by shreyansh jain Active (2.2k points) | 95 views

+2 votes

1 answer

21

Graph Coloring
How many ways are there to color this graph from any $4$ of the following colors : Violet, Indigo, Blue, Green, Yellow, Orange and Red ? There is a condition that adjacent vertices should not be of the same color I am getting $1680$. Is it correct?

asked Nov 27, 2018 in Graph Theory by Balaji Jegan Active (4.9k points) | 314 views

+1 vote

0 answers

22

Ace test series
A medical student has to work in a hospital for five days in january.However,he is not allowed to work two consecutive days in the hospital.in how many different ways can he choose the five days he will work in the hospital? A)C(27,5) B)C(26,5) C)C(27,4) D)C(26,4)

asked Nov 26, 2018 in Combinatory by talha hashim Loyal (5.5k points) | 74 views

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0 answers

23

Zeal Test Series 2019: Combinatory - Permutations And Combinations
in this type question i am finding difficulty to solve please tell me the approach with proper explanation

asked Nov 18, 2018 in Combinatory by Prince Sindhiya Loyal (5.7k points) | 133 views

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0 answers

24

Doubt
can someone explain the formula n^k when k distinguishable items are to be placed in n distinguishable boxes without any restrictions?

asked Nov 16, 2018 in Combinatory by aditi19 Active (5.1k points) | 28 views

+2 votes

1 answer

25

Kenneth Rosen Edition 6th Exercise 5.6 Question 37 (Page No. 390)
How many solutions are there to the equation x1+x2+x3=17 with x1<6, x3>5?

asked Nov 16, 2018 in Combinatory by aditi19 Active (5.1k points) | 332 views

+1 vote

1 answer

26

ACE BOOK,
Number of non-negative integer solutions to the equation $x_{1}+x_{2}+x_{3}+x_{4}=12,$ if each $x_i$ must have one of the values $1,2,3,4$ is_____

asked Nov 16, 2018 in Combinatory by Laxmi Yadav (79 points) | 146 views

0 votes

1 answer

27

Kenneth Rosen Edition 6th Exercise 5.6 Question 25 (Page No. 389)
Suppose that a set S has n elements. How many ordered pairs(A,B) are there such that A and B are subsets of S with A$\subseteq$ B?

asked Nov 14, 2018 in Combinatory by aditi19 Active (5.1k points) | 62 views

+1 vote

1 answer

28

How to find total no of integer solutions to the below equation ?
In X+y+z<=12 , X,y,z>=1 How to find total no of integral solutions ?If you are introducing any dummy variable for solving , please do explain the logic behind this .

asked Nov 11, 2018 in Combinatory by radha gogia Loyal (6.3k points) | 301 views

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0 answers

29

Discrete Maths
The non-negative integral solutions to the equation $x_1+x_2+x_3+x_4 \leq10$ I got 209 as answer.Is it correct?

asked Nov 6, 2018 in Combinatory by Ayush Upadhyaya Boss (27.7k points) | 71 views

0 votes

1 answer

30

Number of sub-strings for a given sub string having repeated symbols
Lets for a a given string aabbbccdd I need to find the number of substrings possible how to go about it? Does the n(n+1)/2 formula work here also?

asked Nov 5, 2018 in Theory of Computation by sripo Active (2.4k points) | 172 views

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author	user:martin
title	title:apple
content	content:apple
exclude	-tag:apple
force match	+apple
views	views:100
score	score:10
answers	answers:2
is accepted	isaccepted:true
is closed	isclosed:true

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