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

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

Let denote the number of triangles which can be formed using the vertices of a regular polygon of sides. If , then equals

A student is allowed to select at most books from collection of books. If the total number of ways in which he can select at least one books is , find the value of

Let be the set of all permutations of such that is not a permutation of for any . Then, the number of elements in is

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

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

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

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

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

There are and 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

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

Statement 1: If a polygon has total diagonals, then the total number of its sides are .
Statement 2: The total number of ways of selecting points out of non-collinear points is .

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

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

The number of diagonals of a polygon with sides is

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

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

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

The number of diagonals of sided polygon are _____.
