Combination

IMPORTANT

Combination: Overview

This topic covers concepts such as Combination, Combinatorics Problems on Polygon, Difference between Permutation and Combination, Selection of 'r' Objects out of 'n' Distinct Objects, Understanding of nCr and its Existence, etc.

Important Questions on Combination

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An examination paper consists of 12 questions divided into parts A & B. Part-A contains 7 questions & Part-B contains 5 questions. A candidate is required to attempt 8 questions selecting 3 at least from each part. In how many maximum ways can the candidate select the questions?

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The total number of paths from the origin to the point 9,9 in the cartesian plane which never pass through 5,5, where paths consisting only of steps going 1 unit North or 1 unit East, is

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Let   T n  denote the number of triangles which can be formed using the vertices of a regular polygon of  n sides. If  Tn+1Tn=21 , then  n equals

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A student is allowed to select at most n books from  collection of   ( 2n+1 ) books. If  the total number of ways in which he can select at least one books is 63, find the value of n

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Let A be the set of all permutations a1,a2,,a6 of 1,2,,6 such that a1,a2,,ak is not a permutation of 1,2,,k for any k, 1k5. Then, the number of elements in A is

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If total number of students is 10 and number of students to be selected or permutated is 5. Find the number of ways of selection and permutation and state the difference between permutation and combination.

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If total number of students is 8 and number of students to be selected or permutated is 6. Find the number of ways of selection and permutation and state the difference between permutation and combination.

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If total number of students is 15 and number of students to be selected or permutated is 7. Find the number of ways of selection and permutation and state the difference between permutation and combination.

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If total number of students is 12 and number of students to be selected or permutated is 4. Find the number of ways of selection and permutation and state the difference between permutation and combination.

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If total number of students is 8 and number of students to be selected or permutated is 4. Find the number of ways of selection and permutation and state the difference between permutation and combination.

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There are 4, 5 and 6 points on the three parallel and co-planar lines. If no set of four or more points is cyclic and no set of three points lying on distinct lines is collinear, then the number of circles passing through exactly three points are

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An urn contains 5 red, 4 black and 3 white marbles. Then, the number of ways in which 4 marbles can be drawn from it so, that at most 3 of them are red, is

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Statement 1: If a polygon has total 66 diagonals, then the total number of its sides are 12.

Statement 2: The total number of ways of selecting 2 points out of n non-collinear points is C2n.

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In how many different ways can the letters of the word DESIGN be arranged so that the vowels are at the two ends?

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A password is set with 3 distinct letters from the word LOGARITHMS. How many such passwords can be formed?

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The number of diagonals of a polygon with 15 sides is

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There are 5 bananas and 4 oranges. In how many different ways fruits can be selected if fruits of same kind are different? (if minimum 1 fruit is selected)

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In a cricket championship there are 36 matches. The number of teams, if each plays 1 match with other are

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In how many ways a team of 5 members can be chosen from 8 members:

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The number of diagonals of 15 sided polygon are _____.