Permutations and Combinations questions
785 published questions with worked solutions.
- Three dice having digits 1, 2, 3, 4, 5 and 6 on their faces are marked I, II and III and rolled. Let x, y and z represent the...
- If P(n, r)=2520 and C(n, r)=21, then what is the value of C(n+1, r+1)?
- If n! has 17 zeros, then what is the value of n?
- If C(20, n+2)=C(20, n-2), then what is n equal to?
- What is the number of ways in which the letters of the word 'ABLE' can be arranged so that the vowels occupy even places?
- If C(3n, 2n)=C(3n, 2n-7), then what is the value of C(n, n-5)?
- How many odd numbers between 300 and 400 are there in which none of the digits is repeated?
- How many permutations are there of the letters of the word 'TIGER' in which the vowels should not occupy the even positions?
- What is the maximum value of n such that 5^n divides (30!+35!), where n is a natural number?
- In how many ways can a team of 5 players be selected out of 9 players so as to exclude two particular players?
- How many four-digit natural numbers are there such that all of the digits are odd?
- If different permutations of the letters of the word 'MATHEMATICS' are listed as in a dictionary, how many words (with or without...
- If n>7, then what is the probability that C(n, 7) is a multiple of 7?
- A box contains 2 white balls, 3 black balls and 4 red balls. What is the number of ways of drawing 3 balls from the box with at...
- What is the number of 6-digit numbers that can be formed only by using 0, 1, 2, 3, 4 and 5 (each once); and divisible by 6?
- Let x be the number of permutations of the word 'PERMUTATIONS' and y be the number of permutations of the word 'COMBINATIONS'....
- What is the maximum number of points of intersection of 10 circles?
- A set S contains (2n+1) elements. There are 4096 subsets of S which contain at most n elements. What is n equal to?
- A man has 7 relatives (4 women and 3 men). His wife also has 7 relatives (3 women and 4 men). In how many ways can they invite 3...
- A triangle PQR is such that 3 points lie on the side PQ, 4 points on QR and 5 points on RP respectively. Triangles are...
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