The Gateway to Computer Science Excellence
For all GATE CSE Questions
Toggle navigation
GATE Overflow
Facebook Login
Google Login
or
Email or Username
Password
Remember
Login
Register

I forgot my password
All Activity
Questions
Unanswered
Tags
Subjects
Users
Ask
Previous
Blogs
New Blog
Exams
First time here? Checkout the
FAQ
!
x
×
Close
Use the google search bar on side panel. It searches through all previous GATE/other questions. For hardcopy of previous year questions please see
here
Recent questions tagged permutationsandcombinations
0
votes
1
answer
1
Combination with repetition allowed
Ans. 0
asked
1 day
ago
in
Mathematical Logic
by
Na462
Active
(
4.6k
points)

26
views
permutationsandcombinations
+1
vote
1
answer
2
Combinations and Permutations
In how many ways can 12 different books be parceled into 4 packets so that 3 of the packets contain 3 books each and one of them two books atleast, if all the packets have the same destination?
asked
3 days
ago
in
Combinatory
by
Devshree Dubey
Boss
(
13.3k
points)

62
views
discretemathematics
permutationsandcombinations
0
votes
0
answers
3
Combinatorics
There are 100 students. 85 choose Math, 80 choose Physics, 75 choose Chemistry, 70 choose Biology. What is the minimum number of students choosing all 4 subjects? Assume each student chosen at least one subject?
asked
4 days
ago
in
Combinatory
by
aditi19
(
261
points)

16
views
permutationsandcombinations
+2
votes
2
answers
4
Permutations with restrictions
$Z =\left \{ {A,B,C,D,E,F,G} \right \}$ How many permutations of all elements of set $Z$ are possible when A cannot appear after D and C cannot appear after F C cannot appear after D
asked
Jul 31
in
Combinatory
by
Mk Utkarsh
Boss
(
14.1k
points)

64
views
permutationsandcombinations
discretemathematics
0
votes
1
answer
5
Discrete maths approach
Can you please guide me how to approach discrete maths? I want prepare it alongside with what's being taught at classroom coaching, please suggest resources and strategy
asked
Jul 30
in
Set Theory & Algebra
by
Ajaaz
(
17
points)

37
views
discretemathematics
permutationsandcombinations
settheory&algebra
mathematicallogic
linearalgebra
0
votes
2
answers
6
Sets and relations
If A is a set of positive odd elements less than 10. Then what is the cardinality of set A?
asked
Jul 28
in
Set Theory & Algebra
by
AIkiran01
(
163
points)

68
views
permutationsandcombinations
settheory&algebra
0
votes
1
answer
7
Permutations
The number of permutations of ‘n’ different things taken not more than ‘r’ at a time, with repetitions being allowed, is (a) (nr – 1)/ (n – 1) (b) (nr – 1) / (n – 1)! (c) n(nr – 1)/ (n – 1) (d) (nr – 1) / n!
asked
Jul 25
in
Combinatory
by
shubham6596
(
163
points)

35
views
permutationsandcombinations
0
votes
3
answers
8
Combinatorics
A company hires 11 new employees, each of whom is to be assigned to one of 4 subdivisions. Each subdivision will get at least one new employee. In how many ways can these assignments be made?
asked
Jul 22
in
Combinatory
by
krishn.jh
Junior
(
743
points)

139
views
permutationsandcombinations
+1
vote
2
answers
9
Permutation and Combination
How many $10$  digit strings of $0's$ and $1's$ are there that do not contain any consecutive $0's$?
asked
Jul 18
in
Numerical Ability
by
imnitish
Junior
(
671
points)

124
views
permutationsandcombinations
recurrence
+1
vote
2
answers
10
Engineering mathematics
$\text{How many 5 letter word can be formed}$ $\text{from 6 a's,6 b's,6 c's,5 d's,5e's,4f's,4g's,3h's,3i's ?}$
asked
Jul 15
in
Combinatory
by
Shivani gaikawad
(
371
points)

50
views
engineeringmathematics
zeal
permutationsandcombinations
0
votes
3
answers
11
Self Doubt
How to evaluate this quickly? $\large\sum^{20}_{r=0}(1)^r\binom{r+2}{r}\\OR\\\large\sum^{20}_{r=0}(1)^r(r+2)(r+1)$
asked
Jul 11
in
Combinatory
by
Soumya29
Boss
(
12.4k
points)

83
views
permutationsandcombinations
0
votes
0
answers
12
Combinatorics Question on Bit Strings
How many bit strings of length 8 contain either three consecutive 0's or four consecutive 1's ? MY APPROACH : Initially, for 3 consecutive 0's: 000_ _ _ _ _ =>2^5 = 32 WAYS 1000_ _ _ _ =>2^4 = 16 WAYS _1000_ _ _ =>2^4 = 16 WAYS _ _1000_ ... =>2*3! = 12 WAYS so, total ways = 112 + 48  12 = 148 ways But answer is given as 147 ways. Where am I wrong?
asked
Jul 6
in
Combinatory
by
Balaji Jegan
Active
(
1.4k
points)

44
views
permutationsandcombinations
counting
discretemathematics
0
votes
1
answer
13
Rosen (Combinatorics)
I am not getting this. Can someone please explain using example. Thank you
asked
Jul 5
in
Combinatory
by
tusharp
Junior
(
805
points)

69
views
discretemathematics
kennethrosen
permutationsandcombinations
0
votes
1
answer
14
Rosen(PnC)
Suppose we consider n=4 and r=2 then bit string formed is like b1,b2,b3,b4 where Bi is bit. Now to ensure exactly two 1's in any of these 4 places we can do it byc(4,2). After this suppose string look like 1,b2,b3,1 now for remaining two bits, each has (n1) options as we want exactly two 1's. so how could just C(n,r) is used here?
asked
Jul 5
in
Combinatory
by
tusharp
Junior
(
805
points)

35
views
kennethrosen
discretemathematics
permutationsandcombinations
0
votes
0
answers
15
Question regarding Catalan Number
I have a question regarding Catalan Number. The question is as follows, Find the number of binary strings w of length 2n with an equal number of 1’s and 0’s and the property that every prefix of w has at least as many as 0’s as 1’s. Now i know the answer for this question is 2nCn/(n+1). I wanted to know how this question relates to Catalan number?
asked
Jul 1
in
Combinatory
by
noxevolution
(
23
points)

43
views
discretemathematics
permutationsandcombinations
+1
vote
0
answers
16
interview IIsc
Given a deck of 10 cards numbered 1 to 10. Select 3 cards one by one. Find the probability that selected cards is in increasing order. Eg : {1, 5, 7} or {8, 9, 10} etc
asked
Jul 1
in
Probability
by
Rishav Kumar Singh
Active
(
2.8k
points)

82
views
probability
permutationsandcombinations
0
votes
1
answer
17
combinatorics
let say there are three elements in a set {1,2,3}.find total #of 4 digit no. which are neither non decreasing nor non increasing.
asked
Jun 28
in
Combinatory
by
Aman Juyal
(
269
points)

47
views
permutationsandcombinations
0
votes
1
answer
18
CombinatoricsKenneth Rosen(Ex 5.341)
How many ways are there for a horse race with three horses to finish if ties are possible.(Two or three horses may tie).
asked
Jun 24
in
Combinatory
by
Ayush Upadhyaya
Boss
(
11.1k
points)

25
views
discretemathematics
permutationsandcombinations
0
votes
2
answers
19
CombinatoricsKenneth Rosen(Ex 5.3 31)
The english alphabet contains 21 consonants and five vowels.How many strings of six lowercase letters of the English alphabet contain (b)Exactly two vowels (d)At least two vowels For (b) part I solved it like choose 2 vowels from 5 in $\binom{5}{2}$ ways ... }*6!))$ and both of my answers don't match with the key in Rosen. Please let me know where I am wrong.
asked
Jun 24
in
Combinatory
by
Ayush Upadhyaya
Boss
(
11.1k
points)

64
views
discretemathematics
kennethrosen
permutationsandcombinations
0
votes
1
answer
20
CombinatoricsKenneth Rosen(Ex5.1 23c)
How many strings of three decimal digits can be formed such that they have exactly two digits that are 4's. My approach as to select 2 positions for these 4's in $\binom{3}{2}$ ways and the last bit will have 10 choices.Now I can permute the string formed in $ ... total such strings should be $\binom{3}{2}$ * 10*$\frac{3!}{2!}$ = 90. But the answer is 27. How?
asked
Jun 23
in
Combinatory
by
Ayush Upadhyaya
Boss
(
11.1k
points)

29
views
kennethrosen
permutationsandcombinations
0
votes
0
answers
21
CombinatoricsSelf doubt
How many outcomes are possible when 10 coins are tossed? $X_{h} + X_{t}$ =10 where $X_{h}$ denotes the number of heads and it is $\geq$0 and $X_{t}$ denotes the number of tails which is also $\geq$0. This comes out to be .$_{10}^{2 ... Shouldn't the answer to the above problem be $2^{10}$ considering each coin can have 2 outcomes either heads or tails? Which one is correct?
asked
Jun 22
in
Combinatory
by
Ayush Upadhyaya
Boss
(
11.1k
points)

47
views
discretemathematics
permutationsandcombinations
0
votes
1
answer
22
CombinatoricsSelf Doubt
In how many ways can we arrange 4 boys and 3 girls in a straight line such that no two girls are together. One approach came to my mind was arrange 4 boys first=4! ways. Now 5 gaps created.Choose 3 for girls and arrange girls=5C3*3! ... !(total ways without restriction) why am I getting a different answer from the former case where I take boys first and then arrange girls?
asked
Jun 22
in
Combinatory
by
Ayush Upadhyaya
Boss
(
11.1k
points)

36
views
discretemathematics
permutationsandcombinations
0
votes
1
answer
23
Distinguishable objects and indistinguishable boxes
asked
Jun 8
in
Mathematical Logic
by
Na462
Active
(
4.6k
points)

115
views
permutationsandcombinations
0
votes
0
answers
24
Number of Max Heap
How many maxheaps can be formed with the following elements? $\{1,1,1,2,2,2,3,3,3,4,4,4\}$
asked
Jun 4
in
DS
by
Balaji Jegan
Active
(
1.4k
points)

158
views
datastructure
permutationsandcombinations
binaryheap
heap
0
votes
1
answer
25
Mind Boggling question
asked
Jun 3
in
Combinatory
by
Balaji Jegan
Active
(
1.4k
points)

88
views
discretemathematics
permutationsandcombinations
factorial
0
votes
1
answer
26
Combinatorics
Among the integers $1,2,3,....,200$ if $101$ integers are chosen,then show that there are two among the chosen,such that one is divisible by the other.
asked
May 29
in
Mathematical Logic
by
Sammohan Ganguly
(
435
points)

69
views
engineeringmathematics
discretemathematics
permutationsandcombinations
pigeonholeprinciple
counting
+1
vote
2
answers
27
Ace booklet
How many ways $4$ boys and $4$ girls can sit in a row so that no two girl are sitting side by side
asked
May 29
in
Mathematical Logic
by
Rahul singh dhakrey
(
25
points)

79
views
engineeringmathematics
permutationsandcombinations
counting
discretemathematics
0
votes
1
answer
28
Combinatorics
Given m integers $a_1,a_2,....,a_m$ show that there exist integers $k,s$ with $0 \leq k < s \leq m$ such that $a_{k+1} + a_{k+2} + .....+a_s$ is divisible by $m$.
asked
May 29
in
Mathematical Logic
by
Sammohan Ganguly
(
435
points)

51
views
engineeringmathematics
discretemathematics
permutationsandcombinations
pigeonholeprinciple
counting
0
votes
1
answer
29
Combinatorics
Show that of any $5$ points chosen within a square of length $2$ there are $2$ whose distance apart is atmost $\sqrt{2}$.
asked
May 28
in
Mathematical Logic
by
Sammohan Ganguly
(
435
points)

33
views
engineeringmathematics
discretemathematics
permutationsandcombinations
pigeonholeprinciple
0
votes
2
answers
30
#Combinatorics
#COMB There are $4$ boys and $6$ prizes are to be distributed among them such that each has at least $1$ prize. How many ways that can be done? My solution: $\text{Case 1 : 3 1 1 1}$ $\text{Case 2 : 2 2 1 11}$ $\text{Case 1 : C(6, ... My doubt is in the second case, am I not considering the prizes to be indistinguishable? I am confused in this regard. Please help me clear this doubt.
asked
May 25
in
Combinatory
by
Abhisek Das
Active
(
1.3k
points)

83
views
permutationsandcombinations
discretemathematics
Page:
1
2
3
4
5
6
...
18
next »
Quick search syntax
tags
tag:apple
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
Recent Posts
Anxiety
Nielit 2018
Donation (Kerala Flood)
Schedule for GATE 2019
GATE 2019 official website
Follow @csegate
Gatecse
Recent questions tagged permutationsandcombinations
Recent Blog Comments
Thanx Mk utkarsh and nikhil bro ... i really ...
Firstly I am not topper. or ranker.
but ...
If you are not able to understand the concept of ...
done:)
Thanx man ... i really appreciate it ...
38,203
questions
45,703
answers
132,818
comments
49,752
users