Permutations and Combinations · Mathematics · WB JEE

Out of 8 given points, 3 are collinear. How many different straight lines can be drawn by joining any two points from those 8 points?

How many odd numbers of six significant digits can be formed with the digits 0, 1, 2, 5, 6, 7 when no digit is repeated?

The number of ways four boys can be seated around a round table in four chairs of different colours is

A polygon has 44 diagonals. The number of the sides is

The number of permutations by taking all letters and keeping the vowels of the word COMBINE in the odd places is

If $${}^{n - 1}{C_3} + {}^{n - 1}{C_4} > {}^n{C_3}$$, then n is just greater than integer

If $${}^n{C_4}$$, $${}^n{C_5}$$ and $${}^n{C_6}$$ are in A.P., then n is

The number of diagonals in a polygon is 20. The number of sides of the polygon is

$${}^{15}{C_3} + {}^{15}{C_5} + \,\,......\,\, + {}^{15}{C_{15}} = $$

The number of ways in which the letters of the word 'VERTICAL' can be arranged without changing the order of the vowels is

n objects are distributed at random among n persons. The number of ways in which this can be done so that at least one of them will not get any object...

Let A be a set containing n elements. A subset P of A is chosen, and the set A is reconstructed by replacing the elements of P. A subset Q of A is cho...

There are n white and n black balls marked 1, 2, 3, ...... n. The number of ways in which we can arrange these balls in a row so that neighbouring bal...

Five letter words, having distinct letters, are to be constructed using the letters of the word 'EQUATION' so that each word contains exactly three vo...

What is the number of ways in which an examiner can assign 10 marks to 4 questions, giving not less than 2 marks to any question?

In a 12 storied building, 3 persons enter a lift cabin. It is known that they will leave the lift at different floors. In how many ways can they do so...

If the total number of m-element subsets of the set A = {a1, a2, ..., an} is k times the number of m element subsets containing a4, then n is...

A candidate is required to answer 6 out of 12 questions which are divided into two parts A and B, each containing 6 questions and he/she is not permit...

There are 7 greeting cards, each of a different colour and 7 envelopes of same 7 colours as that of the cards. The number of ways in which the cards c...

The number of selection of n objects from 2n objects of which n are identical and the rest are different, is

If (2 $$ \le $$ r $$ \le $$ n), then $${}^n{C_r}$$ + 2 . $${}^n{C_{r + 1}}$$ + $${}^n{C_{r + 2}}$$ is equal to

From a collection of 20 consecutive natural numbers, four are selected such that they are not consecutive. The number of such selections is

The number of all numbers having 5 digits, with distinct digits is

Out of 7 consonants and 4 vowels, words are formed each having 3 consonants and 2 vowels. The number of such words that can be formed is

How many triangles can be formed by joining 6 points lying on a circle?

A letter lock consists of three rings with 15 different letters. If N denotes the number of ways in which it is possible to make unsuccessful attempts...

On the occasion of Dipawali festival each student of a class sends greeting cards to others. If there are 20 students in the class, the number of card...