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Recent questions tagged tifr2021
1
votes
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1
TIFR CSE 2021 | Part A | Question: 1
A box contains $5$ red marbles, $8$ green marbles, $11$ blue marbles, and $15$ yellow marbles. We draw marbles uniformly at random without replacement from the box. What is the minimum number of marbles to be drawn to ensure that out of the marbles drawn, at least $7$ are of the same colour? $7$ $8$ $23$ $24$ $39$
A box contains $5$ red marbles, $8$ green marbles, $11$ blue marbles, and $15$ yellow marbles. We draw marbles uniformly at random without replacement from the box. What ...
soujanyareddy13
1.1k
views
soujanyareddy13
asked
Mar 25, 2021
Combinatory
tifr2021
combinatory
pigeonhole-principle
+
–
1
votes
1
answer
2
TIFR CSE 2021 | Part A | Question: 2
What is the area of a rectangle with the largest perimeter that can be inscribed in the unit circle (i.e., all the vertices of the rectangle are on the circle with radius $1$)? $1$ $2$ $3$ $4$ $5$
What is the area of a rectangle with the largest perimeter that can be inscribed in the unit circle (i.e., all the vertices of the rectangle are on the circle with radius...
soujanyareddy13
626
views
soujanyareddy13
asked
Mar 25, 2021
Quantitative Aptitude
tifr2021
quantitative-aptitude
geometry
circle
+
–
2
votes
1
answer
3
TIFR CSE 2021 | Part A | Question: 3
Let $M$ be an $n \times m$ real matrix. Consider the following: Let $k_{1}$ be the smallest number such that $M$ can be factorized as $A \cdot B$, where $A$ is an $n \times k_{1}$ and $B$ is a $k_{1} \times m$ matrix. Let $k_{2}$ be the smallest number ... $k_{1}= k_{2}= k_{3}$ No general relationship exists among $k_{1}, k_{2}$ and $k_{3}$
Let $M$ be an $n \times m$ real matrix. Consider the following:Let $k_{1}$ be the smallest number such that $M$ can be factorized as $A \cdot B$, where $A$ is an $n \time...
soujanyareddy13
653
views
soujanyareddy13
asked
Mar 25, 2021
Linear Algebra
tifr2021
linear-algebra
matrix
rank-of-matrix
+
–
1
votes
1
answer
4
TIFR CSE 2021 | Part A | Question: 4
What is the probability that at least two out of four people have their birthdays in the same month, assuming their birthdays are uniformly distributed over the twelve months? $\frac{25}{48}$ $\frac{5}{8}$ $\frac{5}{12}$ $\frac{41}{96}$ $\frac{55}{96}$
What is the probability that at least two out of four people have their birthdays in the same month, assuming their birthdays are uniformly distributed over the twelve mo...
soujanyareddy13
1.1k
views
soujanyareddy13
asked
Mar 25, 2021
Probability
tifr2021
probability
+
–
1
votes
1
answer
5
TIFR CSE 2021 | Part A | Question: 5
Let $n, m$ and $k$ be three positive integers such that $n \geq m \geq k$. Let $S$ be a subset of $\left \{ 1, 2,\dots, n \right \}$ of size $k$. Consider sampling a function $f$ uniformly at random from the set of all functions mapping $\left \{ 1,\dots, n \right \}$ ... $1-\frac{k!\binom{n}{k}}{n^{k}}$ $1-\frac{k!\binom{n}{k}}{m^{k}}$
Let $n, m$ and $k$ be three positive integers such that $n \geq m \geq k$. Let $S$ be a subset of $\left \{ 1, 2,\dots, n \right \}$ of size $k$. Consider sampling a func...
soujanyareddy13
594
views
soujanyareddy13
asked
Mar 25, 2021
Set Theory & Algebra
tifr2021
set-theory&algebra
functions
probability
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–
1
votes
1
answer
6
TIFR CSE 2021 | Part A | Question: 6
A matching in a graph is a set of edges such that no two edges in the set share a common vertex. Let $G$ be a graph on $n$ $\textit{vertices}$ in which there is a subset $M$ of $m$ $\textit{edges}$ which is a matching. Consider a random process where each vertex in the ... $\left ( 1-p^{2} \right )^{m}$ $1-\left ( 1-p\left ( 1-p \right ) \right )^{m}$
A matching in a graph is a set of edges such that no two edges in the set share a common vertex. Let $G$ be a graph on $n$ $\textit{vertices}$ in which there is a subset ...
soujanyareddy13
768
views
soujanyareddy13
asked
Mar 25, 2021
Graph Theory
tifr2021
graph-theory
graph-matching
probability
+
–
1
votes
1
answer
7
TIFR CSE 2021 | Part A | Question: 7
Let $d$ be the positive square integers (that is, it is a square of some integer) that are factors of $20^{5} \times 21^{5}$. Which of the following is true about $d$? $50\leq d< 100$ $100\leq d< 150$ $150\leq d< 200$ $200\leq d< 300$ $300\leq d$
Let $d$ be the positive square integers (that is, it is a square of some integer) that are factors of $20^{5} \times 21^{5}$. Which of the following is true about $d$?$50...
soujanyareddy13
524
views
soujanyareddy13
asked
Mar 25, 2021
Quantitative Aptitude
tifr2021
quantitative-aptitude
number-theory
+
–
1
votes
0
answers
8
TIFR CSE 2021 | Part A | Question: 8
Consider the sequence $y_{n}=\frac{1}{\int_{1}^{n}\frac{1}{\left ( 1+x/n \right )^{3}}dx}$ for $\text{n} = 2,3,4, \dots$ Which of the following is $\text{TRUE}$? The sequence $\{y_{n}\}$ does not have a limit as $n\rightarrow \infty$ ... and is equal to $0$. The sequence $\{y_{n}\}$ first increases and then decreases as $\text{n}$ takes values $2, 3, 4, \dots$
Consider the sequence$$y_{n}=\frac{1}{\int_{1}^{n}\frac{1}{\left ( 1+x/n \right )^{3}}dx}$$for $\text{n} = 2,3,4, \dots$ Which of the following is $\text{TRUE}$?The seque...
soujanyareddy13
372
views
soujanyareddy13
asked
Mar 25, 2021
Calculus
tifr2021
calculus
limits
+
–
2
votes
2
answers
9
TIFR CSE 2021 | Part A | Question: 9
Fix $n\geq 6$. Consider the set $\mathcal{C}$ of binary strings $x_{1}, x_{2} \dots x_{n}$ of length $n$ such that the bits satisfy the following set of equalities, all modulo $2$: $x_{i}+x_{i+1}+x_{i+2}=0$ ... $3$ $\left | \mathcal{C} \right |=4$. If $n\geq 6$ is not divisible by $3$ then $\left | \mathcal{C} \right |=1$.
Fix $n\geq 6$. Consider the set $\mathcal{C}$ of binary strings $x_{1}, x_{2} \dots x_{n}$ of length $n$ such that the bits satisfy the following set of equalities, all m...
soujanyareddy13
498
views
soujanyareddy13
asked
Mar 25, 2021
Set Theory & Algebra
tifr2021
set-theory&algebra
set-theory
+
–
1
votes
1
answer
10
TIFR CSE 2021 | Part A | Question: 10
Lavanya and Ketak each flip a fair coin (i.e., both heads and tails have equal probability of appearing) $n$ times. What is the probability that Lavanya sees more heads than ketak? In the following, the binomial coefficient $\binom{n}{k}$ counts the number of $k$-element subsets of ... $\sum_{i=0}^{n}\frac{\binom{n}{i}}{2^{n}}$
Lavanya and Ketak each flip a fair coin (i.e., both heads and tails have equal probability of appearing) $n$ times. What is the probability that Lavanya sees more heads t...
soujanyareddy13
556
views
soujanyareddy13
asked
Mar 25, 2021
Probability
tifr2021
probability
binomial-theorem
+
–
1
votes
1
answer
11
TIFR CSE 2021 | Part A | Question: 11
Find the following sum. $\frac{1}{2^{2}-1}+\frac{1}{4^{2}-1}+\frac{1}{6^{2}-1}+\cdots+\frac{1}{40^{2}-1}$ $\frac{20}{41}$ $\frac{10}{41}$ $\frac{10}{21}$ $\frac{20}{21}$ $1$
Find the following sum.$$\frac{1}{2^{2}-1}+\frac{1}{4^{2}-1}+\frac{1}{6^{2}-1}+\cdots+\frac{1}{40^{2}-1}$$$\frac{20}{41}$$\frac{10}{41}$$\frac{10}{21}$$\frac{20}{21}$$1$
soujanyareddy13
675
views
soujanyareddy13
asked
Mar 25, 2021
Combinatory
tifr2021
combinatory
generating-functions
+
–
1
votes
1
answer
12
TIFR CSE 2021 | Part A | Question: 12
How many numbers in the range ${0, 1, \dots , 1365}$ have exactly four $1$'s in their binary representation? (Hint: $1365_{10}$ is $10101010101_{2}$, that is, $1365=2^{10} + 2^{8}+2^{6}+2^{4}+2^{2}+2^{0}.)$ ... $\binom{11}{4}+\binom{9}{3}+\binom{7}{2}+\binom{5}{1}$ $1024$
How many numbers in the range ${0, 1, \dots , 1365}$ have exactly four $1$’s in their binary representation? (Hint: $1365_{10}$ is $10101010101_{2}$, that is, $$1365=2^...
soujanyareddy13
570
views
soujanyareddy13
asked
Mar 25, 2021
Digital Logic
tifr2021
digital-logic
number-representation
binomial-theorem
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–
1
votes
3
answers
13
TIFR CSE 2021 | Part A | Question: 13
What are the last two digits of $7^{2021}$? $67$ $07$ $27$ $01$ $77$
What are the last two digits of $7^{2021}$?$67$$07$$27$$01$$77$
soujanyareddy13
531
views
soujanyareddy13
asked
Mar 25, 2021
Quantitative Aptitude
tifr2021
quantitative-aptitude
modular-arithmetic
+
–
3
votes
1
answer
14
TIFR CSE 2021 | Part A | Question: 14
Five married couples attended a party. In the party, each person shook hands with those they did not know. Everyone knows his or her spouse. At the end of the party, Shyamal, one of the attendees, listed the number of hands that other attendees ... in the list. How many persons shook hands with Shyamal at the party? $2$ $4$ $6$ $8$ Insufficient information
Five married couples attended a party. In the party, each person shook hands with those they did not know. Everyone knows his or her spouse. At the end of the party, Shya...
soujanyareddy13
711
views
soujanyareddy13
asked
Mar 25, 2021
Combinatory
tifr2021
combinatory
counting
+
–
2
votes
0
answers
15
TIFR CSE 2021 | Part A | Question: 15
Let $P$ be a convex polygon with sides $5, 4, 4, 3$. For example, the following: Consider the shape in the plane that consists of all points within distance $1$ from some point in $P$. If $\ell$ is the perimeter of the shape, which of the following ... the given information. $20\leq \ell < 21$ $21\leq \ell< 22$ $22\leq \ell< 23$ $23\leq \ell< 24$
Let $P$ be a convex polygon with sides $5, 4, 4, 3$. For example, the following:Consider the shape in the plane that consists of all points within distance $1$ from some ...
soujanyareddy13
472
views
soujanyareddy13
asked
Mar 25, 2021
Graph Theory
tifr2021
graph-theory
graph-planarity
+
–
2
votes
2
answers
16
TIFR CSE 2021 | Part B | Question: 1
Consider the following statements about propositional formulas. $\left ( p\wedge q \right )\rightarrow r$ and $\left ( p \rightarrow r \right )\wedge \left ( q\rightarrow r \right )$ are $\textit{not }$ ... values $p$ and $q$, $\text{(i)}$ can be either true or false, while $\text{(ii)}$ is always false.
Consider the following statements about propositional formulas.$\left ( p\wedge q \right )\rightarrow r$ and $\left ( p \rightarrow r \right )\wedge \left ( q\rightarrow ...
soujanyareddy13
890
views
soujanyareddy13
asked
Mar 25, 2021
Mathematical Logic
tifr2021
mathematical-logic
propositional-logic
+
–
1
votes
1
answer
17
TIFR CSE 2021 | Part B | Question: 2
Let $L$ be a singly-linked list $X$ and $Y$ be additional pointer variables such that $X$ points to the first element of $L$ and $Y$ points to the last element of $L$. Which of the following operations cannot be done in time that is ... after the last element of $L$. Add an element before the first element of $L$. Interchange the first two elements of $L$.
Let $L$ be a singly-linked list $X$ and $Y$ be additional pointer variables such that $X$ points to the first element of $L$ and $Y$ points to the last element of $L$. Wh...
soujanyareddy13
788
views
soujanyareddy13
asked
Mar 25, 2021
DS
tifr2021
data-structures
linked-list
+
–
2
votes
3
answers
18
TIFR CSE 2021 | Part B | Question: 3
What is the prefix expression corresponding to the expression: $\left ( \left ( 9+8 \right ) \ast 7+\left ( 6\ast \left ( 5+4 \right ) \right )\ast 3\right )+2?$ You may assume that $\ast$ has precedence over $+$? $\ast + +\: 987 \ast \ast \: 6 + + \:5432$ ... $+ + \ast +\: 987 \ast \ast \: 6 + \:5432$ $+ \ast + \ast \: 987+ + \: 6 \ast \:5432$
What is the prefix expression corresponding to the expression:$\left ( \left ( 9+8 \right ) \ast 7+\left ( 6\ast \left ( 5+4 \right ) \right )\ast 3\right )+2?$You may as...
soujanyareddy13
845
views
soujanyareddy13
asked
Mar 25, 2021
DS
tifr2021
data-structures
stack
infix-prefix
+
–
2
votes
1
answer
19
TIFR CSE 2021 | Part B | Question: 4
Consider the following two languages. ... $\text{NP}$ vs. $\text{P}$ question.
Consider the following two languages.$\begin{array}{rcl} \text{PRIME} & = & \{ 1^{n} \mid n \text{ is a prime number} \}, \\ \text{FACTOR} & = & \{ 1^{n}0 1^{a} 01^{b} ...
soujanyareddy13
495
views
soujanyareddy13
asked
Mar 25, 2021
Theory of Computation
tifr2021
theory-of-computation
p-np-npc-nph
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–
1
votes
1
answer
20
TIFR CSE 2021 | Part B | Question: 5
For a language $L$ over the alphabet $\{a, b\}$, let $\overline{L}$ denote the complement of $L$ and let $L^{\ast}$ denote the Kleene-closure of $L$. Consider the following sentences. $\overline{L}$ and $L^{\ast}$ are both context-free. $\overline{L}$ is not ... ? Both (i) and (iii) Only (i) Only (iii) Only (ii) None of the above
For a language $L$ over the alphabet $\{a, b\}$, let $\overline{L}$ denote the complement of $L$ and let $L^{\ast}$ denote the Kleene-closure of $L$. Consider the followi...
soujanyareddy13
678
views
soujanyareddy13
asked
Mar 25, 2021
Theory of Computation
tifr2021
theory-of-computation
context-free-language
+
–
2
votes
2
answers
21
TIFR CSE 2021 | Part B | Question: 6
Consider the following pseudocode: procedure HowManyDash(n) if n=0 then print '-' else if n=1 then print '-' else HowManyDash(n-1) HowManyDash(n-2) end if end procedure How many ‘-’ does HowManyDash$(10)$ print? $9$ $10$ $55$ $89$ $1024$
Consider the following pseudocode:procedure HowManyDash(n) if n=0 then print '-' else if n=1 then print '-' else HowManyDash(n-1) HowManyDash(n-2) end if end procedureHow...
soujanyareddy13
546
views
soujanyareddy13
asked
Mar 25, 2021
Programming in C
tifr2021
programming
recursion
+
–
1
votes
2
answers
22
TIFR CSE 2021 | Part B | Question: 7
Which of the following regular expressions defines a language that is different from the other choices? $b^{\ast }\left ( a+b \right )^\ast a\left ( a+b \right )^ \ast ab^\ast \left ( a+b \right )^{\ast }$ ...
Which of the following regular expressions defines a language that is different from the other choices?$b^{\ast }\left ( a+b \right )^\ast a\left ( a+b \right )^ \ast ab^...
soujanyareddy13
604
views
soujanyareddy13
asked
Mar 25, 2021
Theory of Computation
tifr2021
theory-of-computation
regular-expression
+
–
3
votes
1
answer
23
TIFR CSE 2021 | Part B | Question: 8
Let $A$ and $B$ be two matrices of size $n \times n$ and with real-valued entries. Consider the following statements. If $AB = B$, then $A$ must be the identity matrix. If $A$ is an idempotent (i.e. $A^{2} = A$) nonsingular matrix, then $A$ must be the identity matrix. ... true of $A$? $1, 2 $ and $3$ Only $2$ and $3$ Only $1$ and $2$ Only $1$ and $3$ Only $2$
Let $A$ and $B$ be two matrices of size $n \times n$ and with real-valued entries. Consider the following statements.If $AB = B$, then $A$ must be the identity matrix.If ...
soujanyareddy13
700
views
soujanyareddy13
asked
Mar 25, 2021
Linear Algebra
tifr2021
linear-algebra
matrix
+
–
2
votes
1
answer
24
TIFR CSE 2021 | Part B | Question: 9
Let $L$ be a context-free language generated by the context-free grammar $G = (V, \Sigma, R, S)$ where $V$ is the finite set of variables, $\Sigma$ the finite set of terminals (disjoints from $V$), $R$ the finite set of rules and $S \in V$ the start variable. ... ${L}'=L^{\ast }$ ${L}'=\left \{ xx \mid x \in L \right \}$ None of the above
Let $L$ be a context-free language generated by the context-free grammar $G = (V, \Sigma, R, S)$ where $V$ is the finite set of variables, $\Sigma$ the finite set of term...
soujanyareddy13
671
views
soujanyareddy13
asked
Mar 25, 2021
Theory of Computation
tifr2021
theory-of-computation
context-free-grammar
+
–
2
votes
1
answer
25
TIFR CSE 2021 | Part B | Question: 10
Let $G$ be a connected bipartite simple graph (i.e., no parallel edges) with distinct edge weights. Which of the following statements on $\text{MST}$ (minimum spanning tree) need $\text{NOT}$ be true? $G$ has a unique $\text{MST}$ ... edge. Every $\text{MST}$ in $G$ contains the third lightest edge. No $\text{MST}$ in $G$ contains the heaviest edge.
Let $G$ be a connected bipartite simple graph (i.e., no parallel edges) with distinct edge weights. Which of the following statements on $\text{MST}$ (minimum spanning tr...
soujanyareddy13
694
views
soujanyareddy13
asked
Mar 25, 2021
Algorithms
tifr2021
algorithms
minimum-spanning-tree
+
–
2
votes
2
answers
26
TIFR CSE 2021 | Part B | Question: 11
Suppose we toss a fair coin (i.e., both beads and tails have equal probability of appearing) repeatedly until the first time by which at least $\textit{two}$ heads and at least $\textit{two}$ tails have appeared in the sequence of tosses made. What is the expected number of coin tosses that we would have to make? $8$ $4$ $5.5$ $7.5$ $4.5$
Suppose we toss a fair coin (i.e., both beads and tails have equal probability of appearing) repeatedly until the first time by which at least $\textit{two}$ heads and at...
soujanyareddy13
1.3k
views
soujanyareddy13
asked
Mar 25, 2021
Probability
tifr2021
probability
expectation
+
–
3
votes
1
answer
27
TIFR CSE 2021 | Part B | Question: 12
Let $G$ be an undirected graph. For any two vertices $u, v$ in $G$, let $\textrm{cut} (u, v)$ be the minimum number of edges that should be deleted from $G$ so that there is no path between $u$ and $v$ in the resulting graph. Let $a, b, c, d$ be $4$ ... $\textrm{cut} (b,d) = 2$, $\textrm{cut} (b,c) = 2$ and $\textrm{cut} (c,d) = 1$
Let $G$ be an undirected graph. For any two vertices $u, v$ in $G$, let $\textrm{cut} (u, v)$ be the minimum number of edges that should be deleted from $G$ so that there...
soujanyareddy13
582
views
soujanyareddy13
asked
Mar 25, 2021
Graph Theory
tifr2021
graph-theory
graph-connectivity
+
–
2
votes
1
answer
28
TIFR CSE 2021 | Part B | Question: 13
Let $A$ be a $3 \times 6$ matrix with real-valued entries. Matrix $A$ has rank $3$. We construct a graph with $6$ vertices where each vertex represents distinct column in $A$, and there is an edge between two vertices if the two columns represented ... is connected. There is a clique of size $3$. The graph has a cycle of length $4$. The graph is $3$-colourable.
Let $A$ be a $3 \times 6$ matrix with real-valued entries. Matrix $A$ has rank $3$. We construct a graph with $6$ vertices where each vertex represents distinct column in...
soujanyareddy13
609
views
soujanyareddy13
asked
Mar 25, 2021
Graph Theory
tifr2021
graph-theory
graph-coloring
matrix
+
–
3
votes
2
answers
29
TIFR CSE 2021 | Part B | Question: 14
Consider the following greedy algorithm for colouring an $n$-vertex undirected graph $G$ with colours $c_{1}, c_{2}, \dots:$ consider the vertices of $G$ ... $m\left ( n, r \right ) = nr$ $m\left ( n, r \right ) = n\binom{r}{2}$
Consider the following greedy algorithm for colouring an $n$-vertex undirected graph $G$ with colours $c_{1}, c_{2}, \dots:$ consider the vertices of $G$ in any sequence ...
soujanyareddy13
741
views
soujanyareddy13
asked
Mar 25, 2021
Graph Theory
tifr2021
graph-theory
graph-coloring
+
–
2
votes
1
answer
30
TIFR CSE 2021 | Part B | Question: 15
Let $A\left [ i \right ] : i=0, 1, 2, \dots , n-1$ be an array of $n$ distinct integers. We wish to sort $A$ in ascending order. We are given that each element in the array is at a position that is at most $k$ away from its position in the sorted array, ... $t\left ( n \right ) = \Theta \left ( nk \right )$
Let $A\left [ i \right ] : i=0, 1, 2, \dots , n-1$ be an array of $n$ distinct integers. We wish to sort $A$ in ascending order. We are given that each element in the arr...
soujanyareddy13
790
views
soujanyareddy13
asked
Mar 25, 2021
Algorithms
tifr2021
algorithms
sorting
time-complexity
+
–
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