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JEE • MATHEMATICS • PERMUTATION AND COMBINATION
Permutation and combination practice · Medium
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These sets use single-correct-answer MCQs. They do not cover every JEE Main or JEE Advanced question format and are not full-length mock papers.
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Showing 31-60 of 250 questions
31
Medium
31 of 250
Analyzing
+4 | -1
The number of permutations of the letters of the word 'HINDUSTAN' such that neither the pattern 'HIN' nor 'DUS' nor 'TAN' appear, are
View answer and explanation
Correct option: B
169194
Option D (None of these) is correct because the number of primes in the list is zero, as each term is divisible by a number between 2 and p.
32
Medium
32 of 250
Analyzing
+4 | -1
If the number of ways of selecting cards out of unlimited number of cards bearing the number
2, 3, 4 so that they can not be used to write the number 423 is 93. Then is equal to
2, 3, 4 so that they can not be used to write the number 423 is 93. Then is equal to
View answer and explanation
Correct option: B
5
Option B (5) is correct because the number of ways to select cards such that they cannot be used to write 423 is 93, which leads to the equation 3 * 2^m - 3 = 93, solving for m gives m=5.
33
Medium
33 of 250
Application
+4 | -1
5- digit numbers are to be formed using without repeating the digits. If be the number of such numbers that exceed 20000 and be the number of those that lie between 30000 and 90000 , then is :
View answer and explanation
Correct option: D
Option D (5:3) is correct because the ratio of numbers greater than 20000 to those between 30000 and 90000 is 120:72, which simplifies to 5:3.
34
Medium
34 of 250
Application
+4 | -1
6 white and 6 black balls are distributed among ten identical urns, so that there is atleast one ball in each urn. Balls are all alike except for the colour and each box can hold any number of balls. The number of different distributions of the balls is:
View answer and explanation
Correct option: D
10
Option D (10) is correct because there are 10 distinct ways to distribute the balls among the urns, considering the constraints.
35
Medium
35 of 250
Application
+4 | -1
There are 20 persons among whom two are brothers. The number of ways in which we can arrange them around a circle so that there is exactly one person between the brothers is
View answer and explanation
Correct option: B
!
Option B () is correct because it accounts for arranging the remaining people and the two possible arrangements of the brothers.
36
Medium
36 of 250
Application
+4 | -1
The number of ways in which 10 person can sit around a table so that they do not have same neighbor (all at once) in any two arrangements
View answer and explanation
Correct option: B
Option B () is correct because it accounts for the circular arrangement and the fact that clockwise and anticlockwise arrangements are considered the same.
37
Medium
37 of 250
Application
+4 | -1
The range of the function is
View answer and explanation
Correct option: A
Option A ({1,6,20,24}) is correct because it correctly calculates the values of the permutation function for the valid range of x.
38
Medium
38 of 250
Analyzing
+4 | -1
Let then the exponent of 2 in ! is
View answer and explanation
Correct option: C
15
The correct answer is C (15) because after evaluating the sum E to be 17, the exponent of 2 in 17! is calculated using Legendre's formula.
39
Medium
39 of 250
Analyzing
+4 | -1
cannot be the square of natural number except for , is
View answer and explanation
Correct option: C
1, 3
The correct answer is C (1, 3) because is a perfect square only for n=1 and n=3, and not for other values as the unit digit becomes 3 for n >= 5.
40
Medium
40 of 250
Application
+4 | -1
The number of non-negative integral solutions of , is
View answer and explanation
Correct option: B
Option B () is correct because it represents the number of non-negative integral solutions for the given equation using stars and bars method.
41
Medium
41 of 250
Application
+4 | -1
There are 5 different coloured balls and 5 boxes of the same colour as that of the balls. The number of ways that exactly 2 balls will go to the boxes of their own colour is
View answer and explanation
Correct option: A
20
Option A (20) is correct because it is the number of ways to have exactly 2 balls in their own colored boxes, which involves derangement of the remaining 3 balls.
42
Medium
42 of 250
Application
+4 | -1
In a town the car plate numbers contains only three or four digits, not containing the digit 0. The
maximum number of cars that can be numbered is
maximum number of cars that can be numbered is
View answer and explanation
Correct option: B
7290
Option A (6480) is correct because it sums the possibilities of 3-digit and 4-digit plate numbers without the digit 0.
43
Medium
43 of 250
Analyzing
+4 | -1
A team of four students is to be selected from a total of 12 students. Total number of ways in which team can be selected such that two particular students refuse to be together and other two particular students wish to be together only, is equal to
View answer and explanation
Correct option: C
226
Option D (None of these) is correct because the total number of ways is 226, which is not among the provided options.
44
Medium
44 of 250
Application
+4 | -1
Three straight lines and are parallel and lie in the same plane. Five points are taken on each of , and . The maximum number of triangles which can be obtained with vertices at these points, is
View answer and explanation
Correct option: A
425
Option A (425) is correct because it calculates the total possible triangles minus the degenerate cases where all three points lie on the same line.
45
Medium
45 of 250
Application
+4 | -1
In a polygon, no three diagonals are concurrent. If the total number of points of intersection of diagonals interior to the polygon is 70, then the number of diagonals of the polygon is
View answer and explanation
Correct option: A
20
Option D (None of these) is incorrect. Option A (20) is correct because the number of diagonals is calculated by where n = 8.
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46
Medium
46 of 250
Application
+4 | -1
Four speakers will address a meeting, where speaker will always speak after speaker . Then, the number of ways in which the order of speakers can be prepared is
View answer and explanation
Correct option: D
12
Option D (12) is correct because in half of the total arrangements, speaker Q will speak after speaker P, so the number of ways is .
47
Medium
47 of 250
Application
+4 | -1
The number of ways of arranging letters of the word HAVANA so that and do not appear together is
View answer and explanation
Correct option: B
80
Option B (80) is correct because we calculate the total arrangements of HAVANA and subtract the arrangements where V and N are together.
48
Medium
48 of 250
Application
+4 | -1
From the vertices of a regular polygon of 10 sides, the number of ways of selecting three vertices such that no two vertices are consecutive is
View answer and explanation
Correct option: C
50
Option C (50) is correct because the number of ways to select three non-consecutive vertices is calculated by subtracting the number of ways to select consecutive vertices from the total number of ways to select three vertices.
49
Medium
49 of 250
Application
+4 | -1
Total number of 3 letter words that can be formed from the letter of the word 'AAAHNPRRS' is equal to
View answer and explanation
Correct option: C
247
Option D (227) is the closest to the correct answer, but the provided solution steps are incorrect. The correct approach involves considering different cases of letter combinations.
50
Medium
50 of 250
Application
+4 | -1
Find the number of 6 digits numbers whose sum is 10 using the digits only
View answer and explanation
Correct option: C
90
Option C (90) is correct because it sums the arrangements for all possible cases where the sum of 6 digits using 1, 2, and 3 equals 10.
51
Medium
51 of 250
Application
+4 | -1
Seven different lecturers are to deliver lectures in seven periods of a class on a particular day. and are three of the lecturers. The number of ways in which a routine for the day can be made such that delivers his lecture before and before , is
View answer and explanation
Correct option: D
None of these
The correct answer is None of these because the number of ways to arrange the lectures with A before B and B before C is 840.
52
Medium
52 of 250
Application
+4 | -1
The number of ways in which 5 boys and 3 girls can be seated on a round table if a particular boy and a particular girl never sit adjacent to each other, is :
View answer and explanation
Correct option: A
!
Option A (5 x 6!) is correct because it accounts for arranging the remaining boys and girls around the table after fixing B1 and G1's positions, ensuring they are not adjacent.
53
Medium
53 of 250
Application
+4 | -1
The number of ways in which 6 men can be arranged in a row so that three particular men are consecutive is
View answer and explanation
Correct option: B
Option B () is correct because it treats the three consecutive men as a single unit and then arranges them internally.
54
Medium
54 of 250
Application
+4 | -1
The letters of the word GHOTU is arranged alphabetically as in a dictionary. The rank of the word TOUGH is
View answer and explanation
Correct option: D
89
Option A () is incorrect. Option B () is the correct answer because by using the substitution x = 1/t, the integral can be simplified and solved.
55
Medium
55 of 250
Application
+4 | -1
A round table conference is to be held between 20 delegates of 2 countries. In how many ways can they be seated if two particular delegates are always together
View answer and explanation
Correct option: D
Option D () is correct because treating the two delegates as one unit leaves 19 units to arrange in a circle (18!), and the two delegates can switch places (2!).
56
Medium
56 of 250
Application
+4 | -1
Five distinct letters are to be transmitted through a communication channel. A total number of 15 blanks is to be inserted between the letters with atleast three between every two. The number of ways in which this can be done, is
View answer and explanation
Correct option: C
2400
Option C (2400) is correct because it represents the number of ways to insert 15 blanks between 5 letters with at least 3 blanks between each pair.
57
Medium
57 of 250
Application
+4 | -1
If is the number of positive integral solution of , then the value of is
View answer and explanation
Correct option: D
256
Option D (256) is correct because each prime factor of 770 can be assigned to any of the four variables, resulting in 44 possible solutions.
58
Medium
58 of 250
Application
+4 | -1
If seven women and seven men are to be seated around a circular table such that there is a man on either side of every woman, then the number of seating arrangements is
View answer and explanation
Correct option: A
!
Option A (6!7!) is correct because 7 women can be arranged in 6! ways around a circular table, and then the 7 men can be arranged in 7! ways in the spaces between the women.
59
Medium
59 of 250
Application
+4 | -1
There are 3 set of parallel lines containing respectively lines, lines and lines respectively. The greatest number of parallelograms that can be formed by the system
View answer and explanation
Correct option: D
None of these
Option D (None of these) is correct because the formula provided does not correctly calculate the number of parallelograms.
60
Medium
60 of 250
Application
+4 | -1
The exponent of 12 in 50! is
View answer and explanation
Correct option: A
22
Option A (22) is correct because the exponent of 12 in 50! is determined by the minimum of the exponent of 3 and half the exponent of 2 in the prime factorization of 50!.
Revision notes and key takeaways
Review PERMUTATION AND COMBINATION in your textbook or class notes, then use this set to check your understanding.
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