## Number of permutations such that sum of elements at odd index and even index are equal

Given N numbers, find the number of permutations in which the sum of elements at odd index and sum of elements at even index are… Read More »

Given N numbers, find the number of permutations in which the sum of elements at odd index and sum of elements at even index are… Read More »

Given N numbers which have a permutation of first N numbers. In a single operation, any prefix can be reversed. The task is to find… Read More »

Given N and K. The task is to find out how many different ways are there to represent N as the sum of K non-zero… Read More »

Given two positive integers N and K. The task is to find the number of arrays of size N that can be formed such that… Read More »

Prerequisite : Permutation and Combination Given a polygon of m sides, count number of triangles that can be formed using vertices of polygon. Answer :… Read More »

Prerequisite : Permutation and Combination n students appear in an examination, find the number of ways the result of examination can be announced. Answer is… Read More »

The value of 75C2 is: (A) 1215 (B) 2315 (C) 2775 (D) 1675 Answer: (C) Explanation: 75C2 = 75! / (73! * 2!) = 75*74/2… Read More »

In how many different ways can the alphabets of the word ‘SCORING’ be arranged so that the vowels always come together? (A) 120 (B) 720… Read More »

In how many ways can the alphabets of the word ‘DERAIL’ be arranged so that the vowels come at the odd positions only? (A) 12… Read More »

Out of 8 boys and 10 girls, how many groups of 5 boys and 6 girls can be formed? (A) 11760 (B) 25200 (C) 720… Read More »

Out of 6 engineers and 4 doctors, how many groups of 4 professionals can be formed such that at least 1 engineer is always there?… Read More »

A box contains 2 red coins, 3 green coins and 4 blue coins. In how many ways can 3 coins be chosen such that at… Read More »

Out of 7 boys and 4 girls, how many queues of 3 boys and 2 girls can be formed? (A) 120 (B) 25200 (C) 24800… Read More »

There are 5 floating stones on a river. A man wants to cross the river. He can move either 1 or 2 steps at a… Read More »

In how many ways can 20 boys and 18 girls make a queue such that no two girls are together? (A) 20!* 20C18 (B) 20!*… Read More »