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Recent questions in Combinatory
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Combinatorics:
Counting,
Recurrence relations,
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1
#Pigeonhole Principle Doubt
How many positive integers not exceeding 1000 are divisible by 7? So, the doubt here is why we are taking floor function while calculating this .
asked
3 days
ago
in
Combinatory
by
Abhinavg
(
127
points)

36
views
pegionhole
#counting
0
votes
2
answers
2
GATE question
Q. 6 Xs has to be placed in the figure below such that each row contains at least one X. In how many ways can this be done? a) 160 b) 180 c) 170 d) 26
asked
4 days
ago
in
Combinatory
by
Sachin Kumar Verma
(
49
points)

63
views
permutationsandcombinations
0
votes
0
answers
3
Combinations with 3 Jugs
You are given 3 jugs A,B and C of capacities 8, 5 and 3 liters, respectively. A is filled and B and C are empty. Total amount of water is 8 liters. How many different combinations are possible with at least one of the jug being empty or atleast one of them being full. For example $(8,0,0)$ , $(4,4,0)$ , $(5,3,0)$
[closed]
asked
5 days
ago
in
Combinatory
by
Mk Utkarsh
Boss
(
11.7k
points)

52
views
permutationsandcombinations
0
votes
1
answer
4
Combinatorics
How many ways we can move from a point (a,b) to a point (i,j) in a coordinate system. Here i>a and j>b and at each step you can move to the right or in the upward direction.
asked
5 days
ago
in
Combinatory
by
Kushagra Chatterjee
Junior
(
647
points)

48
views
permutationsandcombinations
engineeringmathematics
general
0
votes
0
answers
5
COMBINATRICS
NUMBER OF WAYS IN WHICH CORNER OF THE SQUARE CAN BE COLORED WITH TWO COLORS. (ITS IS PERMISSIBLE TO USE A SINGLE COLOUR ON ALL FOUR CORNER)
asked
Apr 13
in
Combinatory
by
Ismail
Junior
(
599
points)

42
views
permutationsandcombinations
testbooktestseries
discretemathematic
+1
vote
1
answer
6
COMBINATRICS
NUMBER OF WAYS WE CAN ARRAYS LETTERS OF THE WORD "TESTBOOK" SO THAT NO TWO VOWELS ARE TOGETHER IS
asked
Apr 13
in
Combinatory
by
Ismail
Junior
(
599
points)

56
views
testbooktestseries
permutationsandcombinations
discretemathematic
+1
vote
0
answers
7
Permutation of 4 Gs out of 5 Gs
Given symbols: $GGGGGAAATTTECCS$ No of ways such that exactly 4 Gs out of 5 Gs are together. I am getting$ \frac{11! × 11}{3!×3!×2!} $. Some one verify it?
asked
Apr 12
in
Combinatory
by
Jason
Active
(
1.2k
points)

94
views
permutationsandcombinations
engineeringmathematics
0
votes
1
answer
8
Kenneth Rosen, Generating Functions, Exercise  6.4 QNO33
asked
Apr 12
in
Combinatory
by
Abhinavg
(
127
points)

93
views
kennethrosen
discretemathematics
generatingfunctions
+1
vote
1
answer
9
Permutations
asked
Apr 4
in
Combinatory
by
shivanisrivarshini
Boss
(
14k
points)

78
views
permutationsandcombinations
isisamplepapers
0
votes
1
answer
10
Indistinguishable objects and Indistinguishable boxes
asked
Apr 4
in
Combinatory
by
Na462
Active
(
1.6k
points)

58
views
permutationsandcombinations
+1
vote
2
answers
11
Kenneth Rosen , Recurrence relation, Exercise 6.1 Qno.  19
asked
Apr 2
in
Combinatory
by
Abhinavg
(
127
points)

51
views
0
votes
1
answer
12
Kenneth Rosen Recurrence Relation Example 8
asked
Mar 31
in
Combinatory
by
Abhinavg
(
127
points)

84
views
kennethrosen
recurrence
+1
vote
2
answers
13
Generating functions
What will be the coefficient of x^17 in the expansion of (x+x^2+x^3+x^4+x^5+x^6)^4?
asked
Mar 29
in
Combinatory
by
Mayank Khakharia 1
(
29
points)

96
views
generatingfunctions
discretemathematics
+3
votes
2
answers
14
Combinatorics
Sanjay have 9 distinct paths (1,2,3.....,9) from his home to his work place. He works from Monday to Friday every week, he does not go to work on Saturdays and Sundays. Every Sunday he schedules that which path he will take for each ... The only restriction is that he cannot select even number paths on 2 consecutive days. How many possible combinations he have to make his schedule?
asked
Mar 26
in
Combinatory
by
Mk Utkarsh
Boss
(
11.7k
points)

88
views
permutationsandcombinations
discretemathematics
+1
vote
2
answers
15
Counting Kenneth Rosen Exercise
How many strings with seven or more characters can be formed from the letters of the word $\text{EVERGREEN}$ ?
asked
Mar 22
in
Combinatory
by
Abhinavg
(
127
points)

112
views
discretemathematics
kennethrosen
counting
permutationsandcombinations
+4
votes
1
answer
16
Discrete Mathematics By Kenneth H Rosen Counting
asked
Mar 20
in
Combinatory
by
Sayed Athar
(
93
points)

78
views
discretemathematics
permutationsandcombinations
counting
0
votes
0
answers
17
self doubt
Three men have 4 coats, 5 waist coats, and 6 caps. In how many ways can they wear them? Three men have 4 coats, 5 waist coats, and 6 caps. In how many ways can they wear any type of them?
asked
Mar 18
in
Combinatory
by
Kaluti
Loyal
(
5.3k
points)

34
views
0
votes
0
answers
18
Number of unique solution
Suppose there is an equation $x_{1}+x_{2}+...........x_{r}=n$ Then number of unique solution in this given equation?
asked
Mar 13
in
Combinatory
by
srestha
Veteran
(
81.7k
points)

60
views
counting
0
votes
0
answers
19
sheldon ross
Three balls are to be randomly selected without replacement from an urn containing $20$ balls numbered $1$ through $20$. If we bet that at least one of the balls that are drawn has a number as large as or larger than $17$, what is the probability that we win the bet?
asked
Mar 10
in
Combinatory
by
Ananya Jaiswal 1
Active
(
1.2k
points)

59
views
probability
randomvariable
+1
vote
5
answers
20
Combinatorics
Three ladies have each brought a child for admission to a school. The head of the school wishes to interview the six people one by one, taking care that no child is interviewed before its mother. In how many different ways can the interviews be arranged? $6$ $36$ $72$ $90$
asked
Mar 8
in
Combinatory
by
Junaed Siddiquee
(
179
points)

116
views
permutationsandcombinations
0
votes
1
answer
21
Rosen Example no.  9
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 ... minimum number of direct connections needed to achieve this goal? Please Explain in this question how pigeonhole principle is applied .
asked
Mar 6
in
Combinatory
by
Abhinavg
(
127
points)

43
views
kennethrosen
discretemathematics
counting
0
votes
0
answers
22
Composition of function
"f:A>B & g:C>D are 2 functions then for their composition B should be equal to C." But if B is not equal to C then composition is possible or not? Eg:A={1,2,} B={3,4} C={4,5} D={6,7} then can fog be computed Or not? f={(1,3), (2,4)} g={(4,6),(5,7)} gof={(2,6)} is it true or not? I hope my question could be understood:)
[closed]
asked
Mar 3
in
Combinatory
by
MayankSharma
(
121
points)

27
views
discretemathematics
functions
relations
settheory&algebra
0
votes
0
answers
23
Combinatorics
There are total 21 identical balls in a shop and 7 children. In how many ways can 7 children claim the balls? (it is not necessary to claim all the balls)
asked
Mar 3
in
Combinatory
by
Mk Utkarsh
Boss
(
11.7k
points)

79
views
permutationsandcombinations
+1
vote
1
answer
24
Kenneth Rosen Ex.10 counting
How many ways are there to put four different employees into three indistinguishable offices when each office can contain any number of employees?
asked
Mar 2
in
Combinatory
by
Lakshman Patel RJIT
Loyal
(
7.5k
points)

88
views
kennethrosen
discretemathematics
counting
permutationsandcombinations
+3
votes
1
answer
25
Combination Ex.14 Kenneth Rosen
How many bit strings of length $n$ contain exactly $r$ $1's$?
asked
Feb 28
in
Combinatory
by
Lakshman Patel RJIT
Loyal
(
7.5k
points)

118
views
discrete
discretemathematics
kennethrosen
counting
+1
vote
1
answer
26
Generating function doubt
Please give me clarification
asked
Feb 24
in
Combinatory
by
Lakshman Patel RJIT
Loyal
(
7.5k
points)

222
views
discretemathematics
generatingfunctions
+2
votes
0
answers
27
Extended Binomial Coefficients
Find the value of extended Binomial Coefficient $\binom{1/2}{3}$
asked
Feb 24
in
Combinatory
by
Mk Utkarsh
Boss
(
11.7k
points)

67
views
permutationsandcombinations
generatingfunctions
0
votes
3
answers
28
Self doubt generating function
Equation: $x+y=10$ and we are asked to find out the number of a nonnegative integral solution of this equation.
asked
Feb 23
in
Combinatory
by
Lakshman Patel RJIT
Loyal
(
7.5k
points)

142
views
generatingfunctions
+1
vote
2
answers
29
Sheldon Ross
From 10 married couples, we want to select group of 6 that is not allowed to contain a married couple. How many choices are there?
asked
Feb 20
in
Combinatory
by
Tesla!
Boss
(
15.1k
points)

68
views
sheldonross
permutationsandcombinations
+2
votes
1
answer
30
Sheldon Ross
Prove $\binom{m+n}{r}$ = $\binom{n}{0}\binom{m}{r}+\binom{n}{1}\binom{m}{r1}+... +\binom{n}{r}\binom{m}{0}$
asked
Feb 20
in
Combinatory
by
Tesla!
Boss
(
15.1k
points)

54
views
sheldonross
permutationsandcombinations
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