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How many numbers between 200 and 1200 can be formed with the digits 0, 1, 2, 3, if the repetition of digits is allowed?

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Important Questions on Permutation and Combination

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Ten different letters of an alphabet are given, words with five letters are formed from these given letters. Then, the number of words which have at least one letter repeated is
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How many number divisible by 5 of 6 digit can be made from the digit 2,3,4,5,6,7
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The number of ways in which 3 prizes can be distributed to 4 children, so that no child gets all the three prizes, are
MEDIUM
In how many different ways can the letters of word CANDIDATE can be arranged in such a way that the vowels always come together?
MEDIUM

The number of (a, b, c), where a, b, c are positive integers such that abc = 30, is

MEDIUM
From 6 different novels and 3 different dictionaries, 4 novels and 1 dictionary are to be selected and arranged in a row on a shelf so that the dictionary is always in the middle. The number of such arrangements is:
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If P4n=20nP2 where P denotes the number of permutations, then n= ________
HARD
If 56Pr+6:Pr+354=30800:1, then
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if P5n:P3n is 2:1 than value of n is
EASY
If p6n=20p4n then the value of n is given by
HARD
The number of 4 digit numbers without repetition that can be formed using the digits 1, 2, 3, 4, 5, 6, 7 in which each number has two odd digits and two even digits is
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In how many ways the letters of word 'MACHINE' can be arranged so that vowels will always be together?

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If Prn=840 and Crn=35, then the value of r is equal to
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If Pr+656:Pr+3=30800:154 , then r is equal to
HARD
A five-digit number divisible by 3 is to be formed using the numerals 0, 1, 2, 3, 4 and 5 without repetition. The total number of ways this can be done is
MEDIUM
Two girls and four boys are to be seated in a row in such a way that the girls do not sit together. In how many different ways can it be done?
EASY
a,b,c are three particular speakers among the 10 speakers of a meeting. The number of ways of arranging all the 10 speakers on the dias in a row so that all the three speakers a,b,c do not sit together is
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5 boys and 3 girls are to be seated together such that no two girls are together
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Six identical coins are arranged in a row. The number of ways in which the number of tails is equal to the number of heads is
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How many numbers of four digits can be made by using the digits 3, 5, 6, 7, and 9?  (Repetition of digits is not allowed)