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Recent questions and answers in Combinatory
+1
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1
answer
1
Pgee 2013
You have a box containing 10 black and 10 blue socks.What is the minimum number of times you need to pull out so that you have a pair of the same color?
answered
15 hours
ago
in
Combinatory
by
Manas Mishra
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2.8k
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19
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iiithpgee
0
votes
0
answers
2
Kenneth H Rosen 7th edition
Please see example 6. l am not getting the mathematical insight. Can anyone please tell how they are arriving at the answer.
asked
1 day
ago
in
Combinatory
by
Psnjit
(
207
points)

21
views
kennethrosen
discretemathematics
permutationsandcombinations
+2
votes
1
answer
3
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?
answered
2 days
ago
in
Combinatory
by
ma1999
(
11
points)

131
views
kennethrosen
discretemathematics
permutationsandcombinations
combinatory
0
votes
1
answer
4
Madeeasy Discrete Maths notes
How many 5 letter word possible having atleast 2 a's ?
answered
Apr 9
in
Combinatory
by
tusharp
Loyal
(
6.4k
points)

52
views
madeeasynotes
discretemathematics
permutationsandcombinations
0
votes
1
answer
5
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 ?
answered
Apr 4
in
Combinatory
by
hitendra singh
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1.8k
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53
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permutationsandcombinations
0
votes
0
answers
6
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
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permutationsandcombinations
0
votes
0
answers
7
General Query: Self doubt(Math+Automata)
Can somebody explain What is identity permutation?
asked
Apr 1
in
Combinatory
by
srestha
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111k
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21
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discretemathematics
finiteautomata
0
votes
0
answers
8
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
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1.6k
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22
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permutationsandcombinations
+1
vote
3
answers
9
MadeEasy Subject Test 2019: Combinatory  Permutations And Combinations
Q.The number of ways, we can arrange 5 books in 3 shelves ________.
answered
Mar 26
in
Combinatory
by
Arkaprava
(
45
points)

347
views
discretemathematics
permutationsandcombinations
madeeasytestseries2019
madeeasytestseries
+2
votes
2
answers
10
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
answered
Mar 25
in
Combinatory
by
KINGSLAYER
(
65
points)

2.2k
views
gate2019
engineeringmathematics
discretemathematics
permutationsandcombinations
0
votes
0
answers
11
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
0
votes
1
answer
12
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.
answered
Mar 19
in
Combinatory
by
vizzard110
(
11
points)

149
views
discretemathematics
permutationsandcombinations
madeeasytestseries2019
madeeasytestseries
+1
vote
1
answer
13
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?
answered
Mar 15
in
Combinatory
by
Arkaprava
(
45
points)

125
views
iisc
cds
+10
votes
5
answers
14
TIFR2015A7
A $1 \times 1$ chessboard has one square, a $2 \times 2$ chessboard has five squares. Continuing along this fashion, what is the number of squares on the regular $8 \times 8$ chessboard? $64$ $65$ $204$ $144$ $256$
answered
Mar 15
in
Combinatory
by
Debargha Bhattacharj
(
215
points)

621
views
tifr2015
permutationsandcombinations
+13
votes
5
answers
15
GATE200334
$m$ identical balls are to be placed in $n$ distinct bags. You are given that $m \geq kn$, where $k$ is a natural number $\geq 1$. In how many ways can the balls be placed in the bags if each bag must contain at least $k$ ... $\left( \begin{array}{c} m  kn + n + k  2 \\ n  k \end{array} \right)$
answered
Mar 9
in
Combinatory
by
Debargha Bhattacharj
(
215
points)

2k
views
gate2003
permutationsandcombinations
ballsinbins
normal
+17
votes
3
answers
16
GATE200213
In how many ways can a given positive integer $n \geq 2$ be expressed as the sum of $2$ positive integers (which are not necessarily distinct). For example, for $n=3$ the number of ways is $2$, i.e., $1+2, 2+1$. Give only the answer ... integer $n \geq k$ be expressed as the sum of $k$ positive integers (which are not necessarily distinct). Give only the answer without explanation.
answered
Mar 9
in
Combinatory
by
Debargha Bhattacharj
(
215
points)

990
views
gate2002
permutationsandcombinations
normal
descriptive
+2
votes
1
answer
17
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
answered
Mar 9
in
Combinatory
by
Debdeep1998
Junior
(
635
points)

41
views
kennethrosen
discretemathematics
generatingfunctions
0
votes
1
answer
18
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 $a)3\left ( 1+3x \right )^{2}$ $b)3\left ( 13x \right )^{2}$ $c)2\left ( 1+3x \right )^{3}$ $d)2\left ( 13x \right )^{3}$
answered
Mar 9
in
Combinatory
by
ankitgupta.1729
Boss
(
10.7k
points)

57
views
generatingfunctions
discretemathematics
0
votes
1
answer
19
Kenneth Rosen Edition 6th Exercise 6.1 Example 7 (Page No. 399)
this is an example taken from Rosen. but I’m unable to understand to understand the solution given there can someone pls explain me in details
answered
Mar 4
in
Combinatory
by
Gawade Sahadev
(
291
points)

50
views
kennethrosen
discretemathematics
#recurrencerelations
counting
+8
votes
7
answers
20
Kenneth Rosen Edition 6 Question 45 (Page No. 346)
How many bit strings of length eight contain either three consecutive 0s or four consecutive 1s?
answered
Mar 3
in
Combinatory
by
srestha
Veteran
(
111k
points)

2k
views
permutationsandcombinations
counting
0
votes
1
answer
21
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
answered
Mar 3
in
Combinatory
by
vipul2097
(
165
points)

31
views
0
votes
1
answer
22
#Combinatorics
answered
Mar 1
in
Combinatory
by
Satbir
Loyal
(
5.9k
points)

100
views
0
votes
0
answers
23
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)

41
views
kennethrosen
discretemathematics
0
votes
2
answers
24
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?
answered
Feb 25
in
Combinatory
by
Satbir
Loyal
(
5.9k
points)

70
views
0
votes
2
answers
25
Kenneth Rosen Edition 6th Exercise 5.2 Example 9 (Page No. 350)
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 ... of direct connections needed to achieve this goal? Please Explain in this question how pigeonhole principle is applied .
answered
Feb 24
in
Combinatory
by
Satbir
Loyal
(
5.9k
points)

134
views
kennethrosen
discretemathematics
counting
pigeonholeprinciple
+1
vote
1
answer
26
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.
answered
Feb 24
in
Combinatory
by
Shaik Masthan
Veteran
(
60.2k
points)

49
views
+17
votes
3
answers
27
GATE20005
A multiset is an unordered collection of elements where elements may repeat any number of times. The size of a multiset is the number of elements in it, counting repetitions. What is the number of multisets of size $4$ that can be constructed from n distinct elements so that at least one element occurs exactly twice? How many multisets can be constructed from n distinct elements?
answered
Feb 19
in
Combinatory
by
Priyadrasta Raut
(
373
points)

1.2k
views
gate2000
permutationsandcombinations
normal
descriptive
+1
vote
2
answers
28
Permutations combination
A playoff between two teams consists of atmost five games.The first team that wins three games wins the playoff.In how many different ways can the playoff occur?
answered
Feb 16
by
subhrob
(
373
points)

480
views
+6
votes
4
answers
29
TIFR2018A6
What is the minimum number of students needed in a class to guarantee that there are at least $6$ students whose birthdays fall in the same month ? $6$ $23$ $61$ $72$ $91$
answered
Feb 10
in
Combinatory
by
Satbir
Loyal
(
5.9k
points)

317
views
tifr2018
pigeonholeprinciple
permutationsandcombinations
+17
votes
2
answers
30
TIFR2014A5
The rules for the University of Bombay fiveaside cricket competition specify that the members of each team must have birthdays in the same month. What is the minimum number of mathematics students needed to be enrolled in the department to guarantee that they can raise a team of students? $23$ $91$ $60$ $49$ None of the above.
answered
Feb 10
in
Combinatory
by
Satbir
Loyal
(
5.9k
points)

791
views
tifr2014
permutationsandcombinations
discretemathematics
normal
pigeonholeprinciple
+15
votes
6
answers
31
TIFR2016A15
In a tournament with $7$ teams, each team plays one match with every other team. For each match, the team earns two points if it wins, one point if it ties, and no points if it loses. At the end of all matches, the teams are ordered in the descending order of their ... total number of points a team must earn in order to be guaranteed a place in the next round? $13$ $12$ $11$ $10$ $9$
answered
Feb 10
in
Combinatory
by
Satbir
Loyal
(
5.9k
points)

598
views
tifr2016
permutationsandcombinations
discretemathematics
normal
+22
votes
6
answers
32
GATE2004IT35
In how many ways can we distribute $5$ distinct balls, $B_1, B_2, \ldots, B_5$ in $5$ distinct cells, $C_1, C_2, \ldots, C_5$ such that Ball $B_i$ is not in cell $C_i$, $\forall i= 1,2,\ldots 5$ and each cell contains exactly one ball? $44$ $96$ $120$ $3125$
answered
Feb 9
in
Combinatory
by
Satbir
Loyal
(
5.9k
points)

2.4k
views
gate2004it
permutationsandcombinations
normal
+13
votes
3
answers
33
CMI2010A02
We need to choose a team of $11$ from a pool of $15$ players and also select a captain. The number of different ways this can be done is $ \begin{pmatrix} 15 \\ 11 \end{pmatrix}$ $11$ . $ \begin{pmatrix} 15 \\ 11 \end{pmatrix}$ $15 . 14 . 13 . 12 . 11 .10 . 9 . 8 . 7 . 6 . 5$ $(15 . 14 . 13 . 12 . 11 .10 . 9 . 8 . 7 . 6 . 5) . 11$
answered
Feb 9
in
Combinatory
by
Satbir
Loyal
(
5.9k
points)

599
views
cmi2010
permutationsandcombinations
normal
discretemathematics
0
votes
1
answer
34
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.
answered
Feb 8
in
Combinatory
by
sai charan chakrala
(
285
points)

66
views
counting
permutationsandcombinations
discretemathematic
discretemathematics
+35
votes
8
answers
35
GATE2016127
Consider the recurrence relation $a_1 =8 , a_n =6n^2 +2n+a_{n1}$. Let $a_{99}=K\times 10^4$. The value of $K$ is __________.
answered
Feb 1
in
Combinatory
by
Sambhrant Maurya
Active
(
1.7k
points)

6.8k
views
gate20161
permutationsandcombinations
recurrence
normal
numericalanswers
0
votes
1
answer
36
generating function
answered
Feb 1
in
Combinatory
by
sgrpwr
(
15
points)

77
views
generatingfunctions
discretemathematics
permutationsandcombinations
#discrete
+1
vote
1
answer
37
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
answered
Jan 31
in
Combinatory
by
balchandar reddy san
Active
(
2.9k
points)

51
views
permutationsandcombinations
0
votes
0
answers
38
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
39
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
2
answers
40
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?
answered
Jan 29
in
Combinatory
by
Shaik Masthan
Veteran
(
60.2k
points)

84
views
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