Distribution of Objects into Bins/Groups

Count the number of ways to distribute distinguishable or indistinguishable objects into labeled boxes, groups, or categories subject to constraints.

brazil-enem 2025 Q169 View
A father bought eight different gifts (among which, a bicycle and a cell phone) to give to his three children. He intends to distribute the gifts so that the oldest and youngest children receive three gifts each, and the middle one receives the two remaining gifts. The oldest will receive, among his gifts, either a bicycle or a cell phone, but not both.
In how many distinct ways can the distribution of gifts be made?
(A) 36
(B) 53
(C) 300
(D) 360
(E) 560
cmi-entrance 2017 QA3 4 marks View
10 mangoes are to be placed in 5 distinct boxes labeled $\mathrm{U}, \mathrm{V}, \mathrm{W}, \mathrm{X}, \mathrm{Y}$. A box may contain any number of mangoes including no mangoes or all the mangoes. What is the number of ways to distribute the mangoes so that exactly two of the boxes contain exactly two mangoes each?
cmi-entrance 2021 QB3 10 marks View
You are supposed to create a 7-character long password for your mobile device.
(i) How many 7-character passwords can be formed from the 10 digits and 26 letters? (Only lowercase letters are taken throughout the problem.) Repeats are allowed, e.g., 0001a1a is a valid password.
(ii) How many of the passwords contain at least one of the 26 letters and at least one of the 10 digits? Write your answer in the form: (Answer to part i) $-$ (something).
(iii) How many of the passwords contain at least one of the 5 vowels, at least one of the 21 consonants and at least one of the 10 digits? Extend your method for part ii to write a formula and explain your reasoning.
(iv) Now suppose that in addition to the lowercase letters and digits, you can also use 12 special characters. How many 7-character passwords are there that contain at least one of the 5 vowels, at least one of the 21 consonants, at least one of the 10 digits and at least one of the 12 special characters? Write only the final formula analogous to your answer to part iii. Do NOT explain.
csat-suneung 2005 Q27 (Discrete Mathematics) 3 marks View
How many ordered pairs $( A , B )$ of disjoint subsets of the set $\{ 1,2,3,4,5,6 \}$ are there? [3 points]
(1) 729
(2) 720
(3) 243
(4) 64
(5) 36
csat-suneung 2006 Q17 4 marks View
As shown in the figure, a rectangular solid is made from 12 transparent glass boxes in the shape of identical cubes. If 4 of these glass boxes are replaced with glass boxes of the same size but black in color such that the rectangular solid viewed from above looks like (가) and viewed from the side looks like (나), how many ways can this be done? [4 points]
(1) 54
(2) 48
(3) 42
(4) 36
(5) 30
csat-suneung 2006 Q17 4 marks View
As shown in the figure, a rectangular solid is made from 12 transparent glass boxes in the shape of cubes of equal size. When 4 of these glass boxes are replaced with black glass boxes of the same size, and the view from above looks like (가) and the side view looks like (나), how many ways can this be done? [4 points]
(1) 54
(2) 48
(3) 42
(4) 36
(5) 30
csat-suneung 2007 Q26 (Discrete Mathematics) 3 marks View
In how many ways can 9 identical candies be distributed into 5 identical bags such that no bag is empty? [3 points]
(1) 8
(2) 7
(3) 6
(4) 5
(5) 4
csat-suneung 2009 Q15 4 marks View
A certain volunteer service center operates the following 4 volunteer activity programs every day.
ProgramABCD
Volunteer Activity Hours1 hour2 hours3 hours4 hours

Chulsu wants to participate in one program each day for 5 days at this volunteer service center and create a volunteer activity plan so that the total volunteer activity hours is 8 hours. How many different volunteer activity plans can be created? [4 points]
(1) 47
(2) 44
(3) 41
(4) 38
(5) 35
csat-suneung 2011 Q26 (Discrete Mathematics) 3 marks View
Among the partitions of the natural number 7, how many distinct partitions can be expressed as the sum of natural numbers not exceeding 3? [3 points]
(1) 6
(2) 7
(3) 8
(4) 9
(5) 10
csat-suneung 2017 Q27 4 marks View
Find the total number of ordered triples $( a , b , c )$ of non-negative integers satisfying the following conditions. [4 points]
(a) $a + b + c = 7$
(b) $2 ^ { a } \times 4 ^ { b }$ is a multiple of 8.
csat-suneung 2018 Q18 4 marks View
When distributing 4 distinct balls into 4 distinct boxes without remainder, how many ways are there to distribute them such that there is at least one box containing exactly 1 ball? (Here, there may be boxes with no balls.) [4 points]
(1) 220
(2) 216
(3) 212
(4) 208
(5) 204
csat-suneung 2019 Q12 3 marks View
The number of ways to distribute 8 identical chocolates to four students $\mathrm { A } , \mathrm { B } , \mathrm { C } , \mathrm { D }$ according to the following rules is? [3 points] (가) Each student receives at least 1 chocolate. (나) Student A receives more chocolates than student B.
(1) 11
(2) 13
(3) 15
(4) 17
(5) 19
csat-suneung 2020 Q16 4 marks View
How many ordered pairs $( a , b , c , d )$ of non-negative integers satisfy the following conditions? [4 points] (가) $a + b + c - d = 9$ (나) $d \leq 4$ and $c \geq d$
(1) 265
(2) 270
(3) 275
(4) 280
(5) 285
csat-suneung 2026 Q30 4 marks View
There are 10 empty bags arranged in a row, and 8 balls. Distribute the balls into the bags so that each bag contains at most 2 balls. Find the number of cases satisfying the following conditions. (Here, the balls are indistinguishable from each other.) [4 points] (가) The number of bags containing 1 ball is either 4 or 6. (나) Bags adjacent to a bag containing 2 balls contain no balls.
isi-entrance 2010 Q1 View
There are 8 balls numbered $1,2 , \ldots , 8$ and 8 boxes numbered $1,2 , \ldots , 8$. The number of ways one can put these balls in the boxes so that each box gets one ball and exactly 4 balls go in their corresponding numbered boxes is
(a) $3 \times {}^{8}\mathrm{C}_{4}$
(b) $6 \times {}^{8}\mathrm{C}_{4}$
(c) $9 \times {}^{8}\mathrm{C}_{4}$
(d) $12 \times {}^{8}C_{4}$
isi-entrance 2018 Q30 View
Assume that $n$ copies of unit cubes are glued together side by side to form a rectangular solid block. If the number of unit cubes that are completely invisible is 30, then the minimum possible value of $n$ is:
(A) 204
(B) 180
(C) 140
(D) 84.
isi-entrance 2019 Q1 View
You are given a $4 \times 4$ chessboard, and asked to fill it with five $3 \times 1$ pieces and one $1 \times 1$ piece. Then, over all such fillings, the number of squares that can be occupied by the $1 \times 1$ piece is
(A) 4
(B) 8
(C) 12
(D) 16 .
isi-entrance 2019 Q16 View
A school allowed the students of a class to go to swim during the days March 11th to March 15, 2019. The minimum number of students the class should have had that ensures that at least two of them went to swim on the same set of dates is:
(A) 6
(B) 32
(C) 33
(D) 121 .
isi-entrance 2019 Q18 View
Three children and two adults want to cross a river using a rowing boat. The boat can carry no more than a single adult or, in case no adult is in the boat, a maximum of two children. The least number of times the boat needs to cross the river to transport all five people is:
(A) 9
(B) 11
(C) 13
(D) 15 .
isi-entrance 2022 Q1 View
Consider a board having 2 rows and $n$ columns. Thus there are $2n$ cells in the board. Each cell is to be filled in by 0 or 1.
(a) In how many ways can this be done such that each row sum and each column sum is even?
(b) In how many ways can this be done such that each row sum and each column sum is odd?
jee-advanced 2012 Q41 View
41. The total number of ways in which 5 balls of different colours can be distributed among 3 persons so that each person gets at least one ball is
(A) 75
(B) 150
(C) 210
(D) 243
ANSWER : B
  1. Let $f ( x ) = \left\{ \begin{array} { r l } x ^ { 2 } \left| \cos \frac { \pi } { x } \right| , & x \neq 0 \\ 0 , & x = 0 \end{array} , x \in \mathbb { R } \right.$, then $f$ is
    (A) differentiable both at $x = 0$ and at $x = 2$
    (B) differentiable at $x = 0$ but not differentiable at $x = 2$
    (C) not differentiable at $x = 0$ but differentiable at $x = 2$
    (D) differentiable neither at $x = 0$ nor at $x = 2$

ANSWER : B
  1. The function $f : [ 0,3 ] \rightarrow [ 1,29 ]$, defined by $f ( x ) = 2 x ^ { 3 } - 15 x ^ { 2 } + 36 x + 1$, is
    (A) one-one and onto.
    (B) onto but not one-one.
    (C) one-one but not onto.
    (D) neither one-one nor onto.

ANSWER: B
  1. If $\lim _ { x \rightarrow \infty } \left( \frac { x ^ { 2 } + x + 1 } { x + 1 } - a x - b \right) = 4$, then
    (A) $a = 1 , b = 4$
    (B) $a = 1 , b = - 4$
    (C) $a = 2 , b = - 3$
    (D) $a = 2 , b = 3$
  2. Let $z$ be a complex number such that the imaginary part of $z$ is nonzero and $a = z ^ { 2 } + z + 1$ is real. Then $a$ cannot take the value
    (A) - 1
    (B) $\frac { 1 } { 3 }$
    (C) $\frac { 1 } { 2 }$
    (D) $\frac { 3 } { 4 }$

ANSWER : D
  1. The ellipse $E _ { 1 } : \frac { x ^ { 2 } } { 9 } + \frac { y ^ { 2 } } { 4 } = 1$ is inscribed in a rectangle $R$ whose sides are parallel to the coordinate axes. Another ellipse $E _ { 2 }$ passing through the point $( 0,4 )$ circumscribes the rectangle $R$. The eccentricity of the ellipse $E _ { 2 }$ is
    (A) $\frac { \sqrt { 2 } } { 2 }$
    (B) $\frac { \sqrt { 3 } } { 2 }$
    (C) $\frac { 1 } { 2 }$
    (D) $\frac { 3 } { 4 }$

ANSWER : C
  1. Let $P = \left[ a _ { i j } \right]$ be a $3 \times 3$ matrix and let $Q = \left[ b _ { i j } \right]$, where $b _ { i j } = 2 ^ { i + j } a _ { i j }$ for $1 \leq i , j \leq 3$. If the determinant of $P$ is 2 , then the determinant of the matrix $Q$ is
    (A) $2 ^ { 10 }$
    (B) $2 ^ { 11 }$
    (C) $2 ^ { 12 }$
    (D) $2 ^ { 13 }$

ANSWER : D
  1. The integral $\int \frac { \sec ^ { 2 } x } { ( \sec x + \tan x ) ^ { 9 / 2 } } d x$ equals (for some arbitrary constant $K$ )
    (A) $- \frac { 1 } { ( \sec x + \tan x ) ^ { 11 / 2 } } \left\{ \frac { 1 } { 11 } - \frac { 1 } { 7 } ( \sec x + \tan x ) ^ { 2 } \right\} + K$
    (B) $\frac { 1 } { ( \sec x + \tan x ) ^ { 11 / 2 } } \left\{ \frac { 1 } { 11 } - \frac { 1 } { 7 } ( \sec x + \tan x ) ^ { 2 } \right\} + K$
    (C) $- \frac { 1 } { ( \sec x + \tan x ) ^ { 11 / 2 } } \left\{ \frac { 1 } { 11 } + \frac { 1 } { 7 } ( \sec x + \tan x ) ^ { 2 } \right\} + K$
    (D) $\frac { 1 } { ( \sec x + \tan x ) ^ { 11 / 2 } } \left\{ \frac { 1 } { 11 } + \frac { 1 } { 7 } ( \sec x + \tan x ) ^ { 2 } \right\} + K$

ANSWER : C
  1. The point $P$ is the intersection of the straight line joining the points $Q ( 2,3,5 )$ and $R ( 1 , - 1,4 )$ with the plane $5 x - 4 y - z = 1$. If $S$ is the foot of the perpendicular drawn from the point $T ( 2,1,4 )$ to $Q R$, then the length of the line segment $P S$ is
    (A) $\frac { 1 } { \sqrt { 2 } }$
    (B) $\sqrt { 2 }$
    (C) 2
    (D) $2 \sqrt { 2 }$

ANSWER : A
  1. The locus of the mid-point of the chord of contact of tangents drawn from points lying on the straight line $4 x - 5 y = 20$ to the circle $x ^ { 2 } + y ^ { 2 } = 9$ is
    (A) $20 \left( x ^ { 2 } + y ^ { 2 } \right) - 36 x + 45 y = 0$
    (B) $20 \left( x ^ { 2 } + y ^ { 2 } \right) + 36 x - 45 y = 0$
    (C) $36 \left( x ^ { 2 } + y ^ { 2 } \right) - 20 x + 45 y = 0$
    (D) $36 \left( x ^ { 2 } + y ^ { 2 } \right) + 20 x - 45 y = 0$

ANSWER : A
SECTION II: Multiple Correct Answer(s) Type
This section contains 5 multiple choice questions. Each question has four choices (A), (B), (C) and (D) out of which ONE or MORE are correct. 51. Let $\theta , \varphi \in [ 0,2 \pi ]$ be such that $2 \cos \theta ( 1 - \sin \varphi ) = \sin ^ { 2 } \theta \left( \tan \frac { \theta } { 2 } + \cot \frac { \theta } { 2 } \right) \cos \varphi - 1$, $\tan ( 2 \pi - \theta ) > 0$ and $- 1 < \sin \theta < - \frac { \sqrt { 3 } } { 2 }$. Then $\varphi$ cannot satisfy
(A) $0 < \varphi < \frac { \pi } { 2 }$
(B) $\frac { \pi } { 2 } < \varphi < \frac { 4 \pi } { 3 }$
(C) $\frac { 4 \pi } { 3 } < \varphi < \frac { 3 \pi } { 2 }$
(D) $\frac { 3 \pi } { 2 } < \varphi < 2 \pi$
ANSWER : ACD
  1. Let $S$ be the area of the region enclosed by $y = e ^ { - x ^ { 2 } } , y = 0 , x = 0$, and $x = 1$. Then
    (A) $S \geq \frac { 1 } { e }$
    (B) $S \geq 1 - \frac { 1 } { e }$
    (C) $S \leq \frac { 1 } { 4 } \left( 1 + \frac { 1 } { \sqrt { e } } \right)$
    (D) $S \leq \frac { 1 } { \sqrt { 2 } } + \frac { 1 } { \sqrt { e } } \left( 1 - \frac { 1 } { \sqrt { 2 } } \right)$

ANSWER : ABD
  1. A ship is fitted with three engines $E _ { 1 } , E _ { 2 }$ and $E _ { 3 }$. The engines function independently of each other with respective probabilities $\frac { 1 } { 2 } , \frac { 1 } { 4 }$ and $\frac { 1 } { 4 }$. For the ship to be operational at least two of its engines must function. Let $X$ denote the event that the ship is operational and let $X _ { 1 } , X _ { 2 }$ and $X _ { 3 }$ denote respectively the events that the engines $E _ { 1 } , E _ { 2 }$ and $E _ { 3 }$ are functioning. Which of the following is (are) true ?
    (A) $P \left[ X _ { 1 } { } ^ { c } \mid X \right] = \frac { 3 } { 16 }$
    (B) $P$ [Exactly two engines of the ship are functioning $\mid X ] = \frac { 7 } { 8 }$
    (C) $P \left[ X \mid X _ { 2 } \right] = \frac { 5 } { 16 }$
    (D) $P \left[ X \mid X _ { 1 } \right] = \frac { 7 } { 16 }$

ANSWER : BD
  1. Tangents are drawn to the hyperbola $\frac { x ^ { 2 } } { 9 } - \frac { y ^ { 2 } } { 4 } = 1$, parallel to the straight line $2 x - y = 1$. The points of contact of the tangents on the hyperbola are
    (A) $\left( \frac { 9 } { 2 \sqrt { 2 } } , \frac { 1 } { \sqrt { 2 } } \right)$
    (B) $\left( - \frac { 9 } { 2 \sqrt { 2 } } , - \frac { 1 } { \sqrt { 2 } } \right)$
    (C) $( 3 \sqrt { 3 } , - 2 \sqrt { 2 } )$
    (D) $( - 3 \sqrt { 3 } , 2 \sqrt { 2 } )$

ANSWER : AB
  1. If $y ( x )$ satisfies the differential equation $y ^ { \prime } - y \tan x = 2 x \sec x$ and $y ( 0 ) = 0$, then
    (A) $y \left( \frac { \pi } { 4 } \right) = \frac { \pi ^ { 2 } } { 8 \sqrt { 2 } }$
    (B) $y ^ { \prime } \left( \frac { \pi } { 4 } \right) = \frac { \pi ^ { 2 } } { 18 }$
    (C) $y \left( \frac { \pi } { 3 } \right) = \frac { \pi ^ { 2 } } { 9 }$
    (D) $y ^ { \prime } \left( \frac { \pi } { 3 } \right) = \frac { 4 \pi } { 3 } + \frac { 2 \pi ^ { 2 } } { 3 \sqrt { 3 } }$

ANSWER : AD
SECTION III : Integer Answer Type
This section contains $\mathbf { 5 }$ questions. The answer to each question is a single digit integer, ranging from 0 to 9 (both inclusive). 56. Let $f : \mathbb { R } \rightarrow \mathbb { R }$ be defined as $f ( x ) = | x | + \left| x ^ { 2 } - 1 \right|$. The total number of points at which $f$ attains either a local maximum or a local minimum is
ANSWER : 5
  1. The value of $6 + \log _ { \frac { 3 } { 2 } } \left( \frac { 1 } { 3 \sqrt { 2 } } \sqrt { 4 - \frac { 1 } { 3 \sqrt { 2 } } \sqrt { 4 - \frac { 1 } { 3 \sqrt { 2 } } \sqrt { 4 - \frac { 1 } { 3 \sqrt { 2 } } \ldots } } } \right)$ is

ANSWER : 4
  1. Let $p ( x )$ be a real polynomial of least degree which has a local maximum at $x = 1$ and a local minimum at $x = 3$. If $p ( 1 ) = 6$ and $p ( 3 ) = 2$, then $p ^ { \prime } ( 0 )$ is

ANSWER : 9
  1. If $\vec { a } , \vec { b }$ and $\vec { c }$ are unit vectors satisfying $| \vec { a } - \vec { b } | ^ { 2 } + | \vec { b } - \vec { c } | ^ { 2 } + | \vec { c } - \vec { a } | ^ { 2 } = 9$, then $| 2 \vec { a } + 5 \vec { b } + 5 \vec { c } |$ is

ANSWER : 3
  1. Let $S$ be the focus of the parabola $y ^ { 2 } = 8 x$ and let $P Q$ be the common chord of the circle $x ^ { 2 } + y ^ { 2 } - 2 x - 4 y = 0$ and the given parabola. The area of the triangle $P Q S$ is

ANSWER : 4
jee-advanced 2020 Q14 View
In a hotel, four rooms are available. Six persons are to be accommodated in these four rooms in such a way that each of these rooms contains at least one person and at most two persons. Then the number of all possible ways in which this can be done is $\_\_\_\_$
jee-main 2021 Q63 View
The total number of positive integral solutions $( x , y , z )$ such that $x y z = 24$ is :
(1) 45
(2) 30
(3) 36
(4) 24
jee-main 2022 Q85 View
Let $A$ be a matrix of order $2 \times 2$, whose entries are from the set $\{ 0,1,2,3,4,5 \}$. If the sum of all the entries of $A$ is a prime number $p , 2 < p < 8$, then the number of such matrices $A$ is
jee-main 2024 Q62 View
Number of ways of arranging 8 identical books into 4 identical shelves where any number of shelves may remain empty is equal to
(1) 18
(2) 16
(3) 12
(4) 15