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Recent questions in Combinatory
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Combinatorics:
Counting,
Recurrence relations,
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1
Rosen 7e Exercise6.5 question 45.b page 433
How many ways can n books be placed on k distinguishable shelves if no two books are the same, and the positions of the books on the shelves matter?
asked
4 days
ago
in
Combinatory
by
aditi19
Active
(
2.9k
points)

74
views
kennethrosen
discretemathematics
permutationsandcombinations
combinatory
0
votes
1
answer
2
Madeeasy Discrete Maths notes
How many 5 letter word possible having atleast 2 a's ?
asked
Apr 9
in
Combinatory
by
Prakhar Garg
(
61
points)

50
views
madeeasynotes
discretemathematics
permutationsandcombinations
0
votes
1
answer
3
Self doubt
How is the problem.. Distribute 5 toys such that each of 3 child get atleast 1 Different from sum of 3 no. X+y+z=5 such that each digit >= 1. Plz explain ?
asked
Apr 4
in
Combinatory
by
Manoj Kumar Pandey
(
177
points)

51
views
permutationsandcombinations
0
votes
0
answers
4
Combinatorics
There are 6n flowers of one type and 3 flowers of second type, total no. Of garlands possible?
asked
Apr 2
in
Combinatory
by
Manoj Kumar Pandey
(
177
points)

12
views
permutationsandcombinations
0
votes
0
answers
5
General Query: Self doubt(Math+Automata)
Can somebody explain What is identity permutation?
asked
Apr 1
in
Combinatory
by
srestha
Veteran
(
111k
points)

21
views
discretemathematics
finiteautomata
0
votes
0
answers
6
website
There is 4 coins 1 paisa, 5 paise, 10 paise, 25 paise using these coins we have to make 50 paisa how many combination can we make ?
asked
Mar 31
in
Combinatory
by
Cristine
Active
(
1.6k
points)

22
views
permutationsandcombinations
0
votes
0
answers
7
Allen Career Institute: Discrete Mathematics
A certain software was being tested by using error seeding strategy in which $22$ errors were seeded. $14$ of seeded errors were detected apart from $140$ unseeded errors when the code was tested using the complete test suit. Calculate the estimated no. of undetected errors in the code after complete testing _____
asked
Mar 22
in
Combinatory
by
srestha
Veteran
(
111k
points)

26
views
discretemathematics
permutationsandcombinations
+1
vote
1
answer
8
Model Question IISc CDS CS Written Test Sample question
Anand is preparing a pizza with 8 slices, and he has 10 toppings to put on the pizza. He can put only one topping on each slice but can use the same topping on zero or more slices. In how many unique ways can he prepare the slices so that the same topping is not used in adjacent slices?
asked
Mar 11
in
Combinatory
by
Chaitrasj
Junior
(
993
points)

114
views
iisc
cds
0
votes
1
answer
9
ACE Test Series: Generating Function
The generating function of the sequence $\left \{ a_{0},a_{1},a_{2}..........a_{n}………...\infty \right \}$ where $a_{n}=\left ( n+2 \right )\left ( n+1 \right ).3^{n}$ is $a)3\left ( 1+3x \right )^{2}$ $b)3\left ( 13x \right )^{2}$ $c)2\left ( 1+3x \right )^{3}$ $d)2\left ( 13x \right )^{3}$
asked
Mar 8
in
Combinatory
by
srestha
Veteran
(
111k
points)

57
views
generatingfunctions
discretemathematics
+2
votes
1
answer
10
Rosen 7e, Advance Counting techniques , Question 6.f
Find the generating function for the sequence $\left \{ a_n \right \} where $ $a_n = \Large \binom{10}{n+1} $ ... $\Large \color{red}{ \frac{( 1+x )^{10}  1}{x} }$ Please verify
asked
Mar 7
in
Combinatory
by
Mk Utkarsh
Boss
(
34.8k
points)

41
views
kennethrosen
discretemathematics
generatingfunctions
0
votes
1
answer
11
Rosen Ex.6.1
Find a recurrence relation for the number of ways to lay out a walkway with slate tiles if the tiles are red, green, or gray so that no two red tiles are adjacent and tiles of the same color are considered indistinguishable
asked
Mar 3
in
Combinatory
by
himgta
Active
(
4k
points)

31
views
0
votes
0
answers
12
Pg 345 Question 23, 6th Edition KH Rosen
How many strings of three decimal digits do not contain the same digit three times? have exactly two digits that are 4s? I know question is easy but the answer is not matching with the one given over here Please someone verify.. Does the word “string” mean that we can take 0 as the first digit as well?
[closed]
asked
Feb 27
in
Combinatory
by
MiNiPanda
Boss
(
21.9k
points)

40
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kennethrosen
discretemathematics
+1
vote
1
answer
13
Rosen example 12 Ch 5.2
Show that every sequence of $n^2$+1 distinct real numbers contains a subsequence of length n+1 that is either strictly increasing or strictly decreasing.
asked
Feb 24
in
Combinatory
by
himgta
Active
(
4k
points)

49
views
0
votes
2
answers
14
Kenneth Rosen Example 9 Ch.5.2
Suppose that a computer science laboratory has 15 workstations and 10 servers. A cable can be used to directly connect a workstation to a server. For each server, only one direct connection to that server can be active at any time. We ... 't understand this part. How is it concluded that remaining nine servers are insufficient when at most 59 connections are used?
asked
Feb 23
in
Combinatory
by
himgta
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(
4k
points)

70
views
0
votes
1
answer
15
Self Doubt
From a group of 5 woman and 7 man we have to select a committee consisting of 2 woman and 3 men. Find the total number of ways to select such committed if (1 and 2 are a separate question) 1. Four man refuse to be in the same committee 2. 2 woman refuse to be in the same committee.
asked
Feb 8
in
Combinatory
by
smsubham
Loyal
(
9.2k
points)

66
views
counting
permutationsandcombinations
discretemathematic
discretemathematics
+2
votes
2
answers
16
GATE20195
Let $U = \{1, 2, \dots , n\}$ Let $A=\{(x, X) \mid x \in X, X \subseteq U \}$. Consider the following two statements on $\mid A \mid$. $\mid A \mid = n2^{n1}$ $\mid A \mid = \Sigma_{k=1}^n k \begin{pmatrix} n \\ k \end{pmatrix}$ Which of the above statements is/are TRUE? Only I Only II Both I and II Neither I nor II
asked
Feb 7
in
Combinatory
by
Arjun
Veteran
(
395k
points)

2.2k
views
gate2019
engineeringmathematics
discretemathematics
permutationsandcombinations
+1
vote
1
answer
17
Letters in boxes  combinations
Q .) The number of ways can 5 letter be put in 3 boxes A, B,C such that A has at least 2 letters. My approach: Number of ways to choose 2 letters out of 5 is 5C2. And for each such combination the remaining 3 letter have 3 choice. Therefore 5C2 * 3^3, but this is incorrect. Please point out the fault in my understanding and also the correct way to solve it
asked
Jan 31
in
Combinatory
by
shaz
(
377
points)

49
views
permutationsandcombinations
0
votes
0
answers
18
Arrangement
Number of ways we can arrange 5 books in 3 selves___________
[closed]
asked
Jan 31
in
Combinatory
by
srestha
Veteran
(
111k
points)

87
views
permutationsandcombinations
0
votes
0
answers
19
The number of ways in which we can place 3 white pawns and 3 black pawns on a 3 . 3 Chessboard is equal to
[closed]
asked
Jan 30
in
Combinatory
by
mehul vaidya
Active
(
4.3k
points)

26
views
0
votes
0
answers
20
Arrangement Problem
The number of ways, we can arrange 5 books in 3 shelves ________. Given answer 2520 n=3 r=5 so answer is 31+5 P5= 7p5= 2520 My answer 3*3*3*3*3= 243 Where am I doing wrong? please help
[closed]
asked
Jan 29
in
Combinatory
by
Mayank Bansal
(
83
points)

44
views
permutationsandcombinations
0
votes
2
answers
21
MadeEasy Test Series
What is the number of seven digit integers possible with sum of the digits equal to 11 and formed by using the digits 1, 2 and 3 only?
asked
Jan 29
in
Combinatory
by
mehul vaidya
Active
(
4.3k
points)

84
views
+1
vote
3
answers
22
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
Active
(
1k
points)

347
views
discretemathematics
permutationsandcombinations
madeeasytestseries2019
madeeasytestseries
0
votes
1
answer
23
Ace pregate
Let S={a,b,c,d,e}. Number of strings of length 5 possible with the letters of S , so that atleast two A's are consecutive is? Answer given is : 421
asked
Jan 27
in
Combinatory
by
Vignaneswarkrishna
(
187
points)

44
views
0
votes
1
answer
24
#Combinatorics
asked
Jan 24
in
Combinatory
by
vipul2097
(
165
points)

100
views
0
votes
0
answers
25
ace test series question on number of palindromes
asked
Jan 24
in
Combinatory
by
Shankar Kakde
(
373
points)

28
views
0
votes
0
answers
26
ME ADVANCE TEST
The number of ways in which we can place 3 white pawns and 3 black pawns on a 3 × 3 Chessboard is equal to
asked
Jan 23
in
Combinatory
by
himgta
Active
(
4k
points)

57
views
0
votes
1
answer
27
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
(
263
points)

147
views
discretemathematics
permutationsandcombinations
madeeasytestseries2019
madeeasytestseries
+1
vote
0
answers
28
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
(
19
points)

153
views
discretemathematics
permutationsandcombinations
madeeasytestseries2019
madeeasytestseries
0
votes
1
answer
29
nptel
Q.1 In a country there are coins of denominations $2, $3, $5 and $7. How many different ways are there to pay exactly $10? approach??
asked
Jan 19
in
Combinatory
by
BASANT KUMAR
Active
(
2.4k
points)

33
views
+1
vote
0
answers
30
made easy adv mock
the number of ways in which we can place 3 white pawns and 3 black pawns on a 3*3 chessboard my answer was 12. approach : we cant have any 2 black pawns or 2 white pawns in the same row or column {3*2*1} * {2*1 * 1} am i correct??
asked
Jan 18
in
Combinatory
by
Gate Fever
Active
(
5k
points)

96
views
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