If (n+1)p5 : (n)p6= 2:7 find n?
(i)How many 4 letter words can be formed using the letters of the word 'ARTICLE'. (ii)Find the number of words begin with an vowel
In how many ways 6 boys and 5 girls can be arranged along a row so that (i)all the girls come together (ii)no two girls come together (iii)no two of the same gender come together
Find the number of ways of arranging 15 students A1,A2,...........A15 in a row such that A1,A2,A3 should sit together in a specified order.
(i)Find the number of 4 digit numbers that can be formed using the digits 2,4,5,7,8 (ii)How many of them are divisible by (a)5 (b)25
If the letters of the word PRISON are permuted in all possible ways and the words thus formed are arranged in dictionary order, find the rank of the word PRISON.
If a set A has 6 elements, find the number of elements in the power set of A
Find the number of proper divisors of 15! ?
Find the number of zeros at the end of (100)!
In how many ways can 10 men and 10 women be divided into 10 couples, each consisting of a man and woman.